Chemistry Module Three

Subscript numbers to prefix

1: mono- 2: di- 3: tri- 4: tetra- 5: penta- 6: hexa- 7: hepta- 8: octa- 9: nona- 10: deca-

Why is it important to consider the VSEPR model of an atom when determining the polarity of a molecule?

A molecule will not have a permanent dipole moment if the molecular arrangement is symmetrical.

Anion

A negatively charged atom (gains electrons)

What are dipoles, and how are they formed?

A pair of opposite charges separated by distance.

Cation

A positively charged atom (lost electrons)

Explain the relationship between valence electrons and bonding.

All chemical bonds involve valence electrons, but bonds are classified by the way electrons are distributed within them.

Give an example that is an exception to using location to determine bond type.

Beryllium and chlorine are far apart from one another on the periodic table but beryllium is 1.57 and chlorine is 3.16; the different is 1.59 which is less than 1.7 so beryllium and chloride form a covalent bond.

Why does nitrogen form three covalent bonds when it bonds to another nitrogen?

Each nitrogen needs three more electrons to reach a stable configuration, so they share three pairs, forming a triple bond.

How is the Roman numeral system, also known as the Stock system, used to name compounds with transition metals? Give an example.

The Roman numeral names the charge of the ion in parentheses in the compound's name.

What is a formula unit?

The formula of an ionic compound that represents the simplest whole number ratio of ions in the compound, not the actual number of each ion present in the crystal.

How do ion charges differ for the fourth main group column and the transition metals?

The fourth main group column depends on the bond they form with other elements.

The greater the difference in their electronegativity values, the more ______ the chemical bond between two atoms.

The greater the difference in their electronegativity values, the more ionic the chemical bond between two atoms.

What causes electronegativity to decrease going down a group?

The shielding effect of the inner electrons, this decreases the attraction.

How do hydrogen bonds form between water molecules?

The slightly positive hydrogen is attracted to the slightly negative oxygen of another molecule, which creates an intermolecular force between the water molecules.

What is electronegativity?

The tendency of an atom to attract electrons (gain electrons.)

List the steps to naming a covalent compound.

1. Add a prefix to the name of the first element to represent the number of atoms of the element in the bond (needed only if there is more than one) 2. Add a prefix to represent the number of atoms of the second element to the root of the second element's name. Add the ending -ide to the last element.

Describe the steps used to create Lewis dot structures to represent covalent bonds.

1. Count how many valence electrons you have in total that will be bonded. 2. Determine how many atoms of each element are needed to satisfy the octet rule for each atom. 3. Place the least electronegative element (farthest from the top right corner of the periodic table) in the center of the molecule. The central atom will always be the least electronegative of the elements in the bond, except for hydrogen, which cannot be a central atom because it only bonds once. 4. A shared electron pair (two electrons) is represented by a line.

show examples, explain how to create a noble gas notation to represent the valence electrons of an element.

1. Find your element on the periodic table (example: Chlorine) 2. Go up a row and find the last element in that row, should be a noble gas (It would be Neon for Chlorine) 3. Use the symbol for that noble gas in shorthand and then write the rest of the configuration to complete it. ( [Ne] 3s23p5)

What steps should you follow to write a chemical formula for an ionic compound?

1. Identify the charge of each of the ions in the compound 2. Write the cation first, followed by the anion. For most ionic compounds, this corresponds to the locations of metals and nonmetals on the periodic table. 3. Br- (anion) and Ca2+ (cation) to become Ca2+and Br-) Determine the ratio of positive to negative ions needed to make the compound neutral (a net charge of zero). Use the "crossing the charges" method, which means the number of the charge (not the sign) of the cation becomes the subscript of the anion, and vice versa. 4. Make sure the subscripts represent the lowest whole number ratio for the ionic compound. 5. Check your work: Make sure the net charge of the formula is zero. Take the charge of each ion multiplied by its subscript, and then add them together

Describe the steps to naming an ionic compound.

1. The element that forms the positive ion is the first word in the name of the compound. 2. Name the negative ion second by shortening its root word and adding -ide to the ending.

What are the steps to create Lewis dot diagrams to show bonding?

1. Use Lewis dot notation for each atom involved in the bond. 2. Use arrows to depict the transfer of electrons in an ionic bond (remember the octet rule-atoms will lose or gain electrons to get a full set of eight valence electrons) 3. This results with the formation of two ionis 4. Both atoms now have complete octets, and the electron shells are stable.

What are polyatomic ions, and what type of bond holds the elements of a polyatomic ion together?

A charged group of covalently bonded atoms. Made up of more than one atom in a covalent bond, but has an overall positive or negative charge because electrons have been gained or lost, there are positive and negative polyatomic ions with a variety of charges.

What is a chemical formula?

A formula giving the number of atoms of each of the elements present in one molecule of a compound. It shows the composition of a compound.

Chemical Bond

A link between two atoms resulting from the mutual attraction of their nuclei for valence electrons.

What is a diatomic molecule?

A molecule composed of only two atoms of the same or different chemical elements.

Any bond with an electronegativity difference of less than ____ is a covalent bond.

Any bond with an electronegativity difference of less than 1.7 is a covalent bond.

List the various sources of carbon in the environment.

Atmosphere, fossil fuels, rocks, shells, soil, surface ocean, plants and trees, ocean life, animals.

Describe the octet rule.

Atoms for elements in the main element groups prefer to have up to eight valence electrons. This fits the periodic table, with eight tall columns and several shorter columns for transition metals.

What did Lewis's octet rule propose?

Atoms of all elements had between one and eight electrons in their outermost, or valence, shell.

Bonds that have a difference in electronegativity ranging from ____ to ____ are ionic bonds.

Bonds that have a difference in electronegativity ranging from 1.7 to 4.0 are ionic bonds.

How are covalent bonds represented with Lewis dot structures?

By a straight line, each line represents a pair of shared electrons.

How is the electron geometry of a molecule determined?

By the number of bonded electrons and lone pair electrons around the central atom.

The atoms of which element are in all organic compounds?

Carbon atoms are in all organic compounds.

Describe the bonding tendencies of carbon

Carbon has four valence electrons and has a tendency to share those electrons in four single bonds, two double, or a single and a triple bond, to achieve a full octet.

Describe where carbon is found.

Carbon is a nonmetal that is found in nature both as a pure element and in various compounds, it is one of the most important elements to humans because it is found in all living matter.

The atoms of which elements do carbon atoms readily bond with?

Carbon is readily to bond with hydrogen, oxygen, nitrogen, sulfur, phosphorus, and the halogen.

Tetrahedral-Four Domains

Central Atom has: 4 bonded atoms, 0 lone pairs VSEPR shape: Tetrahedral Molecular structure: tetrahedral Central Atom has: 3 bonded atoms, 1 lone pairs VSEPR shape: Tetrahedral Molecule structure: trigonal pyramidal Central Atom has: 2 bonded atoms, 2 lone pairs VSEPR shape: tetrahedral Molecule Structure: bent Tetrahedral molecules exist in four domains. A molecule with four domains could have the following configurations: four bonded atoms and zero lone pairs on the central atom (AX4) three bonded atoms and one lone pair on the central atom (AX3E) two bonded atoms and two lone pairs on the central atom (AX2E2) one bonded atom and three lone pairs on the central atom (AXE3)

Linear-One Domain

Central atom has: 1 bond, 0 lone pairs VSEPR shape: linear Molecular structure: linear A molecule with one domain will have a total of one bonded atom and zero lone pairs on the central atom. It has a chemical formula of AX, where A is assigned as the central atom and X is the bonded atom to A.

Line-Two Domains

Central atom has: 2 bonded atoms, 0 lone pairs VSEPR Shape: linear Molecule structure: linear A molecule with two domains will have a total of one bonded atom and one lone pair on the central atom, or two bonded atoms and zero lone pairs on the central atom. Possible chemical formulas for this type of molecule are: AX2 or AXE, where A is assigned as the central atom, X is the bonded atom to A, and E is the lone pair on A.

Trigonal Planar-Three Domains

Central atom has: 3 bonded atoms 0 lone pairs VSEPR shape: trigonal planar Molecule structure: trigonal planar Central atom has: 2 bonded atoms, 1 lone pairs VSEPR shape: trigonal planar Molecule structure: bent A molecule with three domains will have three possible chemical formulas and configurations around the central atom. three bonded atoms and zero lone pairs (AX3) two bonded atoms and one lone pair (AX2E) one bonded atom and two lone pairs (AXE2)

How do carbon atoms often naturally bond with each other?

Charbon atoms often naturally bond with each other in chains, rings, plates, or networks.

What is the first thing you should do to determine whether a chemical formula represents an ionic or covalent bond?

Check the electronegativity of each element within a bond.

How do covalent bonds form?

Covalent bonds form between atoms of similar electronegativities.

Describe covalent bonds.

Covalent bonds occur when two nonmetal atoms share electrons to achieve a stable configuration of the noble gases.

Dipole-dipole

Dipole-dipole forces are electrostatic interactions of permanent dipoles in polar molecules. Since opposites attract, the positive end of one polar molecule and the negative end of another polar molecule tend to align the molecules or increase the attraction.

Describe double bonds.

Double covalent bonds involve two shared pairs of electrons.

Why are valence electrons mostly found in the s and p sublevels of the outermost energy level in an atom?

Each subshell has its own unique shape, subshells d and f have some challenges to bonding that the s and p subshells do not have. That is why d and f electrons are not usually included in the valence and are rarely involved in chemical reactions.

How many electrons are in the valence shell of noble gases?

Eight electrons, a full outer shell

Electron pairs exist in many positions, or ___, around a central atom. How is this number determined?

Electron pairs exist in many positions, or domains, around a central atom. The number of domains is the sum of bonded atoms and lone pairs of electrons surrounding the central atom.

________ and ________ energy influence the attractive forces between ions that form ionic bonds.

Electronegativity and ionization energy influence the attractive forces between ions that form ionic bonds.

Elements in the first group of the periodic table have just one electron in their outer shell. Describe the pattern for the other tall columns.

Elements in the first group have one electron in their outer shell, the second group has two, and the last group has a full outer shell of eight electrons. These are the most chemically unreactive of all the elements.

How can you determine an ion's charge from its group position on the periodic table?

Elements in the same group of the periodic table have the same number of electrons in their valence energy levels, so they tend to have the same charge when they form naturally occurring ions.

How do you use electronegativity to determine bond type?

Elements with a difference in electronegativity lower than 1.7 will bond covalently. Elements with a difference in electronegativity above 1.7 will bond ionically.

Polymers

Extremely long molecule chains with repeated molecular units called monomers. They can be hundreds or thousands of atoms total. Examples: plastics, nylon, polystyrene

How can you determine the number of valence electrons from an electron configuration?

Find the highest energy level that has been occupied by electrons, find how many electrons are in that energy level.

What are functional groups in organic chemistry?

Functional groups are covalently bonded atoms within molecules that are responsible for the chemical characteristics of those molecules. They have their own unique molecular structures and undergo similar chemical reactions no matter what molecule the functional group is bonded to. The exception to this is when a functional group is bonded to another functional group, which changes its chemical reactivity slightly.

Describe what you learned about valence electrons for each group of the periodic table.

Groups 1 and 2: All the elements in column one have one valence electron in their outermost shell. For column two, atoms have two valence electrons. Transition Metals: transition metals follow unique rules, so their columns cannot directly tell us about their total valence electrons. Scientists determine their valence electrons in other ways. Groups 3-7: Just like columns one and two, taller columns three through seven indicate the number of valence electrons for the elements within them. Group 8: With the exception of helium, which only needs two electrons to fill its outermost shell, all other elements in column eight have eight valence electrons.

Hydrogen Bonding

Hydrogen bonds are strong dipole-dipole interactions, not actual bonds. They only occur between molecules containing N-H, O-H, or F-H bonds. Hydrogen forms highly polar covalent bonds with the highly electronegative elements N, O, and F. Hydrogen's small atomic radius allows two molecules containing these polar bonds to come in very close contact with each other, increasing the attraction between the dipoles of each molecule.

How do intermolecular forces compare to intramolecular forces?

Intramolecular is the force between atoms in a chemical compound, intermolecular is the force between compounds/molecules.

How can you remember the seven diatomic elements?

I Bring Clay For Our New House Iodine Bromine Chlorine Fluorine Oxygen Nitrogen Hydrogen

What types of multiple bonds exist?

If an element can form more than one bond, it can do so with multiple single bonds or make a double bond or triple bond.

How is ionization energy used to predict the charges of ions?

If the ionization energy is low, then the electron will be lost more easily.

If the valence electrons equal eight, the element is ________. What does this mean regarding reactivity?

If the valence electrons equal eight, the element is inert, which means it doesn't react with other substances.

When are prefixes not used for naming covalent compounds?

If there is only one atom of the first element in the compound, no prefix is used. On the other hand, a prefix is always used for the second element, even if there is only one atom as in carbon monoxide, CO. Do note that the vowel on a prefix may be dropped if the element name begins with a vowel.

How do van der Waals forces hold molecules together?

In a molecule, one atom will have a more positive and a more negative side, these will attract to other molecules.

Explain how electrons interact in covalent bonds.

In compounds held together by covalent bonds, electrons do not migrate from one atom to another. Instead they are shared by the atoms.

Why does it take less energy to evaporate a liquid than to break the bonds within molecules?

Intermolecular forces are usually much weaker than intramolecular forces.

Ion-Dipole forces

Ion-dipole forces are attractive forces that result from the electrostatic attraction between an ionic compound and a polar molecule, commonly found in solution. Because there is a full charge on the ions and a partial charge on the dipole molecules, ion-dipole forces are stronger than dipole-dipole forces, but not as strong as ionic bonds. For example, when NaCl is added to water, the cation (Na+) is attracted to the partially negative end of the water polar molecule, while the anion (Cl-) is attracted to the ?

What is the difference between ionic and covalent bonds?

Ionic bond: electrostatic attractions between positive and negative ions. This means that electrons are given up by one atom and gained by another atom, and then those atoms are attracted to each other.

Ionic bonds form when one or more ________ are transferred between two atoms.

Ionic bonds form when one or more electrons are transferred between two atoms.

Ionic bonds, which involve the transfer of electrons, occur when the difference in electronegativity between two elements exceeds ______ on the Pauling scale.

Ionic bonds, which involve the transfer of electrons, occur when the difference in electronegativity between two elements exceeds 1.6 on the Pauling scale.

How are ionic and covalent bonds different? Compound Consistency

Ionic solids tend to be brittle, which means they break apart instead of bending or denting. This is because the positive and negative ions are arranged in a grid-like pattern. If you apply enough force to move the ions, then the repulsion between like charges can cause the ionic crystal to crack and break. Covalent compounds are not as brittle because they do not have the strong electrostatic repulsions when the particles are moved.

How are ionic and covalent bonds different? Melting and Boiling Point

Ions have a strong electrostatic attraction to other ions all around them, not just in one direction. This means it takes a lot of energy to pull them apart. Covalent compounds have strong attractions to their shared electrons but relatively weak attractions between molecules compared to the attractions between ions. This means it does not take as much energy to pull molecules apart in phase changes. That is why ionic solids have higher melting and boiling points than covalent solids.

Why does hydrogen form a single bond with another hydrogen?

It needs one additional electron to fill its valence shell, so it shares it with the other hydrogen atom.

What special properties does hydrogen bonding give to water?

Its surface tension is high and the liquid water is able to spread like a film, pool into droplets, and remain in droplets on vertical surfaces like a window despite the downward pull of gravity.

What ability does carbon have that life is based on?

Life is based on carbon's ability to form diverse molecular structures.

Combine lithium and neon. Why don't they bond together?

Lithium will not bond with Neon, neon is a noble gas. It already has eight valence electrons, so therefore it is unreactive and there is no reaction.

London dispersion

London dispersion forces occur between all molecules and particles but are the only force of attraction between nonpolar molecules or noble gas atoms. It is the weakest of the intermolecular forces. London dispersion forces are temporary attractive forces that result when adjacent molecules form instantaneous, or temporary

List the four types of intermolecular forces in order of strength.

London dispersion, dipole-dipole, hydrogen bonding, and ion-dipole

Carbohydrates

Made up of aldehydes or ketones bonded together in more complex structures, they have the empirical formula of CH2O. They are the structural elements in the cell walls of bacteria and plants and the exoskeletons of invertebrates, and they serve as energy storage. Carbohydrates are the starting materials for many organic compounds like fats and amino acids. Example: sucrose

Hydrocarbons

Made up only of carbon and hydrogen. Carbons may be bonded with single, double, or triple bonds and may form chains, branched chains, or ring structures. Examples: octane and benzene

How are ionic and covalent bonds different? Elements within bond

Metals and nonmetals react together to exchange electrons, forming ions that bond together in ionic compounds. Two of the same nonmetal or two nonmetals with very similar electronegativity values (near each other on the periodic table) will form nonpolar covalent bonds because they have similar attraction for the shared electrons. Two nonmetals with a difference of electronegativity between 0.5 and 1.7 will form a polar covalent bond because the shared electrons will spend more time around the more electronegative atom. This gives the bond a partial negative charge on that end and a partial positive charge on the other.

Metals have a ______charge equal to the number of valence electrons they _____.

Metals have a positive charge equal to the number of valence electrons they lose.

Metals tend to _____ electrons and nonmetals tend to ____ electrons to give them full valence shells like a noble gas.

Metals tend to lose electrons and nonmetals tend to gain electrons to give them full valence shells like a noble gas.

How do scientists predict the polarity of molecules?

Molecular polarity is dependent on the difference in electronegativity between atoms in a compound and the molecular asymmetry of the compound's structure. Polarity also influences other physical properties, such as melting and boiling points, solubility, and the interactions between molecules.

What is the molecular shape? How is it different from electron geometry?

Molecular shape, also called molecule structure, is a general shape of the molecule that considers the repulsive and attractive forces between electrons pairs. VSEPR geometry includes unshared electron pairs, if any, on the central atom that determines the geometry. The molecule structure is the atoms only and the shape the atoms make when bonded together. VSEPR is the arrangement of electrons, Molecular is the arrangement of atoms.

Does the strength of dispersion forces increase or decrease with the number of electrons within molecules?

More electrons, the greater the dispersion forces.

What causes electronegativity to increase going left to right on the periodic table?

More protons are added as electrons are added so the attraction between the protons and electrons are stronger.

How do nonmetal atoms gain a full valence shell?

Nonmetal atoms share electrons by overlapping half-filled orbitals from their valence shells. This gives both atoms in the covalent bond a full valence shell of eight electrons.

What is a general pattern to determine bond type based on element type?

Nonmetals bond together covalently Metals bond with nonmetals ionically

Nonmetals have a ____ electronegativity except for the noble gases, which are assigned an electronegativity of _____.

Nonmetals have a high electronegativity except for the noble gases, which are assigned an electronegativity of zero.

Nonmetals have a _______ charge equal to the number of electrons they need to ______ to fill their valence shell.

Nonmetals have a negative charge equal to the number of electrons they need to add to fill their valence shell.

Distribution of nonpolar molecules?

Nonpolar molecules have an even distribution of charge due to all nonpolar bonds, or symmetrical polar bonds that "cancel out."

Explain how position on the periodic table relates to an element's reactivity.

On the left side of the periodic table, the atoms are more reactive since they have less valence electrons and as you move to the right, atoms become less reactive because they have more valence electrons and the last column has eight valence electrons, so they are unreactive.

Carbonyl group

Organic compounds that contain a carbon atom double-bonded to an oxygen atom. Depending on where the carbonyl group appears on the organic compound and what else is bonded to it, the compound may fall into the category of ketone, aldehyde, amide, carboxylic acid, or ester. Example: Acetone

Amines

Organic compounds that contain the amine group, a nitrogen atom bonded to one, two, or three carbons. They are less soluble than alcohol, are usually basic, and often have a strong odor. Example: caffeine

Ethers

Organic compounds that have an oxygen atom bonded between two carbon atoms in the carbon chain. They are not very soluble in water. Example: diethyl ether (an early anesthetic)

Alcohols

Organic compounds with a hydroxyl group (−O-H) bonded to them. They are usually soluble in water because of the polar hydroxyl group. Examples: ethanol and isopropyl alcohol

Describe the three dipole types and how they are formed.

Permanent Dipoles: These occur when atoms in a molecule have substantially different electronegativity and form polar bonds. If the polar bonds are arranged asymmetrically, the molecule has a permanent dipole moment and is a polar molecule. Instantaneous Dipoles: These chance occurrences happen when moving electrons are briefly more concentrated in one place than another within a molecule, creating a temporary dipole. A molecule is polarized when it carries an instantaneous or an induced dipole. Induced Dipoles: These temporary dipoles can occur when one molecule with a permanent dipole repels another molecule's electrons, "inducing" a dipole moment in that molecule temporarily.

Distribution of polar molecules?

Polar molecules have a partial negative end and a partial positive end due to asymmetric arrangement of polar bonds.

Name some of the important molecules made possible by hydrogen bonding.

Proteins, nucleic acids, polymers

What is ionization energy?

The amount of energy it takes to remove one electron from an atom's outermost shell.

The atoms of elements can lose, gain, or even share _______. How many are needed for stable configurations?

The atoms of other elements can lose, gain, or even share electrons. Eight electrons are needed to achieve the stable configuration.

How do the intermolecular forces between molecules affect the boiling point of a substance?

The boiling point of substances often reflects the strength of the intermolecular forces between the molecules. The stronger the intermolecular forces, the greater the energy required to pull the molecules apart and enter the vapor phase, which means they have a higher boiling point.

What is organic chemistry?

The chemistry of carbon atoms.

How does ionization energy determine the bonding behavior of an element?

The difference in first ionization energies determines the type of bond that will form between two elements.

What is the benefit of using Lewis dot structures to represent valence electrons?

The dots around the symbol of the element shows the valence electrons. This provides a clue about how an atom will or will not react with other atoms.

Describe what happens in the video when two hydrogen atoms come close together.

The electron from one hydrogen atom is attracted by the nucleus of the other hydrogen atom. This causes the two atoms to share the two electrons to achieve a stable configuration.

What are intermolecular forces?

The force of attraction between separate molecules.

When a substance is heated, what bonds are broken? What bonds are not broken?

The intermolecular bonds are broken, but the bonds between the atoms in each single molecule are not.

Describe dipole moments with molecules.

The measurement of the polarity of a chemical bond.

Describe the number of covalent bonds.

The number of covalent bonds an atom can form is usually equal to the number of electrons it needs to fill its valence shell.

The outermost shell is the ____ energy level that contains ___ in an atom.

The outermost shell is the highest energy level that contains electrons in an atom. The valence electrons within the outermost shell can be removed from one atom and given to another. These electrons can also be shared with atoms of other elements. This is how atoms undergo chemical reactions or bond with other atoms.

When one element has higher electronegativity than another, such as in a water molecule, what happens?

The oxygen has a stronger electronegativity and will pull stronger on the hydrogen, which causes the oxygen to be slightly negative and the hydrogen to be slightly negative.

How do polyatomic ions form ionic bonds with other elements?

The polyatomic ion can be overall negative and then form an ionic bond with another positive atom because they are opposites and attract.

What do prefixes represent when naming covalent compounds?

The prefix is used to represent the subscript (not a charge) on each of the elements in the molecule.

As molecules increase in electrons, what happens to their melting and boiling points?

Their melting and boiling points increase.

Describe two pure forms of carbon: Diamond and Graphite

These two forms of carbon have very different properties due to the difference in how the carbon atoms are covalently bonded together. Diamond: Diamonds are the hardest known material. This solid form of carbon is colorless and has an extremely high density of3.514g/cm3. In a diamond, the carbon atoms are held together by all single bonds formed in a three-dime. Because the atoms are all held together with covalent bonds, there are no intermolecular forces. This formation holds the carbon atoms together in a strong and compact structure that makes diamonds strong and dense. Graphite: is a soft, black, solid form of carbon that conducts electricity reasonably well and is easily broken. The "lead" in your pencil is graphite. The carbon atoms in graphite are arranged in layers of thin hexagonal "plates" This configuration of carbon atoms is due to the fact that each carbon atom has one double bond and two single bonds, forming a trigonal planar shape of bonds around each carbon atom. The thin layers of carbon atoms in graphite are only held together by the weak London dispersion intermolecular forces, which explains why graphite is so soft and easily broken.

Why do scientists use noble gas configurations to represent valence electrons?

They are only looking at the valence electrons, so the other orbitals are not necessary information

Why does oxygen form two covalent bonds when it bonds to another oxygen?

They both need two more electrons to reach a stable configuration, so they each share two electrons.

Why are transition metals more "eager" to react with substances than transition metals to the right of the periodic table?

They have less valence electrons so they want to fill it up to eight more eagerly than the atoms that have 6 or 7 valence electrons.

Hydrogen and helium don't follow the octet rule. Why? (Hint: Think about the capacity of the first energy level of an atom.)

They only need two electrons to fill up the first energy shell, not eight.

What elements can form more than one possible charge as positive ions?

Transition metals

Describe triple bonds.

Triple bonds involve three shared pairs of electrons.

What is the Valence Shell Electron Pair Repulsion Theory?

VSEPR is used to predict the geometry and shape of a molecule.

Whether ionic or covalent, what does bonding always involve?

Valence Electrons

How do electron pairs guide the shape of a molecule?

Valence electron pairs, whether bonded or unbonded (lone pairs) repel one another. Lone pairs and bonded pairs will spread out and position themselves around the central so they are as far away from each other as possible.

Why do substances stick together?

Van der waals forces. Intermolecular bonding

Describe what occurs in and results from a molecule being polar.

When a molecule is polar, a separation in electrical charge causes opposite electrical charges on opposing sides of the molecule. This results in a slightly positive side of the molecule and a slightly negative side.

How are ionic and covalent bonds different? Bonding

When a molecule is polar, a separation in electrical charge causes opposite electrical charges on opposing sides of the molecule. This results in a slightly positive side of the molecule and a slightly negative side. A covalent bond forms when two atoms with a strong attraction for electrons interact and overlap half-filled orbitals to share electrons.

How are ionic and covalent bonds different? Dissolve in Water

When an ionic compound like table salt, sodium chloride, is placed in water it will dissolve into smaller pieces, and eventually the ions dissociate, or break apart, and diffuse throughout the water. Covalent compounds can dissolve and diffuse, but they do not break apart (dissociate) like ionic compounds. For example, sugar, a covalent compound, will diffuse into the water, but the molecules will stay intact because none of the covalent bonds will break.

Combine hydrogen and fluorine. Describe how they bond.

When hydrogen and fluorine move toward each other, their outermost electrons orbits overlap. One electron from each of their outer orbits started orbiting both nuclei.

Explain what happens as more electrons are shared between atoms.

When more electrons are shared between the two atoms, the bond is stronger and the atoms are pulled closer together, making the bond shorter.

Describe how nonpolar covalent bonds are formed.

When nonmetals share their electrons equally. This occurs if the element or have very similar electronegativity values (a different less than 0.5)

Describe how polar covalent bonds are formed.

When nonmetals share their electrons unequally, meaning one atom has a higher electronegativity than the other (difference of 0.5 to 1.7) This means the shared electrons spend more time near the more electronegative atom, giving that the end of the bond is a partially negative charge. The other side of the bond will have partially positive charge.

Combine sodium and fluorine. Describe how they bond.

When sodium and fluorine get close together (but before their orbits touch), one electron from the outermost orbit of sodium will move to the outermost orbit of fluorine. Sodium now becomes a positively charged atom whereas fluorine now has a negative charge. The two atoms now move together but their orbits do not overlap.

When is there an exception to the covalent naming system?

When the metal bonding covalently is a transition metal, which can share different numbers of electrons depending on the bond.

Describe how atoms with a large difference in electronegativity form ionic bonds

When two atoms have a large difference in electronegativity, the atom with the greater electronegativity can take one or more electrons from the other atom. The atom that receives an electron becomes an anion, leaving the other atom (with fewer electrons) as a cation.

How does electronegativity determine the bonding behavior of an element?

When you bring two elements together which have very similar electronegativities, they tend to form a covalent bond. That is, they share an electron when they bond. If they're quite far apart in electronegativities, they form ionic bonds

show how an electron configuration is converted to a Lewis dot structure.

Write the symbol of the element Find out how many valence electrons the element has Add dots, starting at the top and going clockwise

Neutral Atom

neutral when proton and electrons are equal