Chemistry 101 Week 6
How many lone pairs must an atom possess to have trigonal pyramidal molecular structure? Select the correct answer below: 0 1 2 3
Correct answer: 1 If an atom has four electron domains and precisely one of them is a lone pair, it will have trigonal pyramidal molecular structure.
A trigonal planar molecule will have bond angles of __________. Select the correct answer below: 180 degrees 120 degrees 109.5 degrees 90 degrees
Correct answer: 120 degrees Three electron domains will adopt a trigonal planar orientation with 120∘ bond angles.
In the ionic compound, Ba(NO3)2, what is the charge of the cation? Use the periodic chart below. Select the correct answer below: 2+ 2− 3+ 3−
Correct answer: 2+ The cation is barium. If you look on the periodic chart, barium is in the second column. Each of the elements in this column has 2 valence (outer shell) electrons which means they would carry a 2+ charge when combining with an anion.
The scale of electronegativity has a range of zero to ___: Select the correct answer below: 1 4 10 100
Correct answer: 4 Linus Pauling chose an arbitrary relative scale for electronegativity, ranging from 0 to 4 .
The octet rule predicts that carbon will tend to make ____ bonds. Select the correct answer below: 1 2 3 4
Correct answer: 4 With four valence electrons, carbon will gain an octet by making four covalent bonds.
How many shared electrons and lone pairs does the nitrogen atom in the following polyatomic ion have? A Lewis structure shows the ion Upper S double bond Upper C double bond Upper N. The structure is enclosed in brackets and to the right is a Superscript minus. Both the Upper S and Upper N atoms have 2 lone electron pairs. Select the correct answer below: 2 shared electrons, 2 lone pairs 4 shared electrons, 2 lone pairs 2 shared electrons, 4 lone pairs 4 shared electrons, 4 lone pairs
Correct answer: 4 shared electrons, 2 lone pairs Each pair of dots is a lone pair of electrons. Each line is a bond representing a shared pair of electrons. Therefore, the double bond between N and C contains 4 shared electrons. There are 2 lone pairs for the N atom in this polyatomic ion. The entire polyatomic ion has 4 bonds and 4 lone pairs.
In the Lewis structure below, the nitrogen atom interacts with how many valence electrons? A Lewis structure shows Upper O single bond Upper N double bond Upper O. The single-bonded oxygen atom has 3 lone electron pairs, the nitrogen atom has 1 lone electron pair, and the double-bonded Upper O has 2 lone electron pairs. The structure is enclosed in brackets and has a minus 1 charge. Select the correct answer below: 5 3 2 8
Correct answer: 8 The N atom interacts with eight valence electrons: the 2 electrons in the lone pair and the 6 in the bonds. Notice, there is a double bond between nitrogen and the oxygen on the right where 4 electrons are shared, and there is a single bond between the nitrogen and the oxygen on the left where 2 electrons are shared.
What is the Lewis structure for NH3? Select the correct answer below: A Lewis structure is shown. An N atom is single-bonded to 3 H atoms. A Lewis structure is shown. An N atom is single-bonded to 3 hydrogen atoms. The N atom has a lone pair of electrons. A Lewis structure is shown. On the left is an N atom with 3 lone electron pairs single-bonded to an H atom which is single-bonded to 2 other H atoms.
Correct answer: A Lewis structure is shown. An N atom is single-bonded to 3 hydrogen atoms. The N atom has a lone pair of electrons. We first calculate the number of valence electrons (5+3(1)=8). Then we draw a skeleton and connect atoms to the central atom (hydrogen is never the central). We cannot place any electrons on the terminal atoms. We place remaining electrons on the central atom (one lone pair on nitrogen).
What is the Lewis structure for CO2? Select the correct answer below: A Lewis structure is shown. There is a C atom double-bonded to 2 oxygen atoms. A Lewis structure is shown. There is a central C atom which is double-bonded to 2 O atoms. Each O atom has 2 pairs of electrons shown. A Lewis structure is shown with a central C atom single-bonded to 2 O atoms. Each O atom has 3 lone electron pairs.
Correct answer: A Lewis structure is shown. There is a central C atom which is double-bonded to 2 O atoms. Each O atom has 2 pairs of electrons shown. We can count valence electrons (4+2(6))=16 and draw a skeleton with single bonds to the central atom. We then distribute electrons to the terminal atoms and rearrange to create multiple bonds in order to achieve an octet. Each O is double bonded to C with 2 lone pairs on each O.
What is the Lewis symbol for chlorine? Select the correct answer below: A Lewis structure is shown. A C l atom is surrounded by 4 electron pairs. A Lewis structure of chlorine is shown. The chlorine atom has 3 electron pairs and one unpaired electron. A Lewis structure of chlorine is shown. The chlorine atom has 3 electron pairs. A Lewis structure of chlorine is shown. The chlorine atom has 1 electron pair.
Correct answer: A Lewis structure of chlorine is shown. The chlorine atom has 3 electron pairs and one unpaired electron. Cl has 7 valence electrons.
What is the Lewis symbol for aluminum? Select the correct answer below: A Lewis symbol contains an Al atom. It has a single electron above it, a single electron to its left, and a single electron to its right. A Lewis structure shows an Al atom with 2 electrons on the left, 1 on the top, 1 on the bottom, and 1 on the right. Figures a through d show four different representations of C H subscript 4. Figure a is C H subscript 4. Figure b shows Lewis structure with a C atom in the center that is singly bound to four H atoms: to the right, the left, on the top, and on the bottom. Figure c shows a ball and stick model with a big black sphere in the center and four smaller white spheres, each connected by tubular-shaped bonds to the center sphere. The image looks three-dimensional, with each of the white spheres on the vertices of a tetrahedral. Figure d looks similar to figure c. It has a black sphere, which is connected with four white spheres. The white spheres look like they are merged about one-third into the black sphere. The white spheres are arranged in a tetrahedral pattern.
Correct answer: A Lewis symbol contains an Al atom. It has a single electron above it, a single electron to its left, and a single electron to its right. Al has 3 valence electrons.
What type of bond will form between two atoms that have a difference in electronegativity equal to 0.2? Select the correct answer below: A pure covalent bond. A polar covalent bond. An ionic bond. The bond type depends on the elements.
Correct answer: A pure covalent bond. Consider the following diagram. Two flow charts and table are shown. The first flow chart is labeled, "Electronegativity difference between bonding atoms." Below this label are three rounded text bubbles, connected by a downward-facing arrow, labeled, "Zero," "Intermediate," and "Large," respectively. The second flow chart is labeled, "Bond type." Below this label are three rounded text bubbles, connected by a downward-facing arrow, labeled, "Pure covalent," "Polar covalent," and "Ionic," respectively. A double ended arrow is written vertically to the right of the flow charts and labeled, "Covalent character decreases; ionic character increases." The table is made up of two columns and four rows. The header line is labeled "Bond type" and "Electronegativity difference." The left column contains the phrases "Pure covalent," "Polar covalent," and "Ionic," while the right column contains the values "less than 0.4," "between 0.4 and 1.8," and "greater than 1.8." A difference in electronegativity of 0.2 is not a large enough difference to classify the bond as a polar covalent bond; therefore, it will be a pure or nonpolar covalent bond.
Why do ionic compounds not conduct electricity in their crystalline form? Select the correct answer below: Electricity can only be conducted when atoms are moving. Electricity cannot be conducted when ions are moving. Electricity can only be conducted when ions are moving. Electricity can only be conducted when no ions are present
Correct answer: Electricity can only be conducted when ions are moving. Electricity can only be conducted when ions are moving. In their crystalline form, the ions in the ionic compound are locked tightly in one place.
True or False? In solid form, an ionic compound is electrically conductive. Select the correct answer below: True False
Correct answer: False In solid form, an ionic compound is not electrically conductive because its ions are unable to flow (electricity is the flow of charged particles). When molten, however, it can conduct electricity because its ions are able to move freely through the liquid.
__________ consist of electrostatic forces of attraction between oppositely charged ions (cations and anions). Select the correct answer below: Covalent bonds Nonpolar covalent bonds Polar covalent bonds Ionic bonds
Correct answer: Ionic bonds Ionic bonds consist of electrostatic forces of attraction between oppositely charged ions (cations and anions). These occur between metals (which form cations) and nonmetals (which form anions). Covalent bonds do not occur between ions.
What is used to represent valence electron configurations of atoms and monatomic ions? Select the correct answer below: orbital diagrams Bohr models Lewis symbols energy diagram
Correct answer: Lewis symbols Lewis symbols are used to represent valence electron configurations of atoms and monatomic ions. A Lewis symbol consists of an elemental symbol surrounded by one dot for each of its valence electrons.
Who is credited with deriving the electronegativity values of the periodic table? Select the correct answer below: Alfred Nobel Linus Pauling John Dalton Antoine Lavoisier
Correct answer: Linus Pauling Linus Pauling derived the electronegativity values for each element in the periodic table. Pauling derived the first electronegativity values by comparing the amounts of energy required to break different types of bonds. He chose an arbitrary relative scale ranging from 0 to 4.
Use the periodic table below to answer the question that follows. Predict the likely ion formation and charge of sulfur. Select the correct answer below: S+ S2+ S− S2−
Correct answer: S2− Sulfur is in group 16 which is two groups left of the noble gases. Elements in group 16 will have a tendency to gain two electrons, giving them a charge of 2−.
All of the following compounds feature ionic bonds except __________. Select the correct answer below: Li2O SO2 Ca3P2 FeO
Correct answer: SO2 SO2 is a covalent compound (with covalent bonds) since both sulfur and oxygen are nonmetals. The other choices each contain a pair of one metal element and one nonmetal element which would form ionic compounds with ionic bonds.
Which of the following is an exception to the octet rule? Select the correct answer below: Carbon in CO2 Oxygen in H2O Sulfur in SO2−4 Phosphorus in PH3
Correct answer: Sulfur in SO2−4 Sulfur in SO2−4 is an exception to the octet rule. In this case, sulfur is said to have an expanded octet because it has more than 8 electrons in its valence shell. The Lewis structure for SO2−4 contains two S=O double bonds and two S−O single bonds. These bonds are all covalent bonds, and so the central sulfur atom shares these electron pairs with the oxygen atoms to fill its valence shell. There are 8 electrons in the two S=O double bonds and 4 electrons in the two S−O single bonds. Therefore, the central sulfur atom has 12 electrons in its valence shell.
What is the Lewis structure of C2H6? Select the correct answer below: The center of the structure is 2 C atoms, with one pair of electrons between them. Each C atom is surrounded by 3 H atoms. There is a pair of electrons between each C and H atom. A Lewis structure is shown. The center of the structure is 2 C atoms with two pairs of electrons between them. Each C atom is surrounded by 3 H atoms. There is a pair of electrons between each C atom and H atom. The center of the structure is 2 H atoms with two pairs of electrons between them. The central H atoms are surrounded by 2 H atoms and 1 C atom each. There is a pair of electrons between the each surrounding atom and the central H atoms. A Lewis structure is shown. The center of the structure is 2 H atoms with two pairs of electrons between them. The central H atoms are surrounded by 2 H atoms and 1 C atom each. There is a pair of electrons between each surrounding atom and the central H atoms. The C atoms each have an additional 3 pairs of electrons.
Correct answer: The center of the structure is 2 C atoms, with one pair of electrons between them. Each C atom is surrounded by 3 H atoms. There is a pair of electrons between each C and H atom. We count valence electrons (2(4)+6(1) = 14) and draw a skeleton with bonds to the central atom (hydrogen is never the central atom).
Which is true regarding ionic compounds? Select the correct answer below: They consist of discrete, neutral molecules. Electrons are shared. The total positive charge equals the total negative charge. none of the above
Correct answer: The total positive charge equals the total negative charge. The total positive charge equals the total negative charge in an ionic compound, which is why they are neutral as a whole.
Which of the following allows us to predict the molecular structure? Select the correct answer below: hypervalence theory VSEPR theory electron-deficient theory none of the above
Correct answer: VSEPR theory VSEPR theory (valence shell electron-pair repulsion theory) allows us to predict molecular structure. It can predict the approximate bond angles and bonds/lone pairs around a central atom because of the underlying assumption that electron pairs will attempt to minimize repulsions by maximizing the distance between each other in order to have the most stable structure.
The bond angles around a central atom can be approximated using Select the correct answer below: hyper valence theory. Bohr's theory. electron-deficient theory. VSEPR theory.
Correct answer: VSEPR theory. VSEPR theory (valence shell electron-pair repulsion theory) allows for the prediction of molecular structure. It can predict the approximate bond angles and bonds/lone pairs around a central atom because of the underlying assumption that electron pairs will attempt to minimize repulsions by maximizing the distance between each other.
Why does water have a bent molecular geometry giving it a positive net dipole instead of a linear molecular geometry that would cancel the net dipole? Select the correct answer below: The hydrogen atoms are attracted to one another. The hydrogens are repelled by each other. Water has a bent molecular shape due to the lone pairs on the oxygen atom. The dipole moment is actually 0, and the molecule is linear.
Correct answer: Water has a bent molecular shape due to the lone pairs on the oxygen atom. Water has a bent molecular shape due to the lone pairs on the oxygen atom. The lone pairs add two extra regions of electron density which cause the hydrogen atoms to be slightly repelled and take on a bent structure.
Which of the following does NOT have trigonal planar electron-pair geometry? Select the correct answer below: BF3 AlCl3 XeO3 BH3
Correct answer: XeO3 BF3, AlCl3, and BH3 all have three bonds and zero lone pairs of electrons and therefore have trigonal planar electron-pair geometry. XeO3 has three bonds and one lone pair of electrons which means it has tetrahedral electron-pair geometry.
What forms when two pairs of electrons are shared between a pair of atoms? Select the correct answer below: a single bond a double bond a triple bond none of the above
Correct answer: a double bond A double bond forms when two pairs of electrons are shared between a pair of atoms.
What forms when three electron pairs are shared by a pair of atoms? Select the correct answer below: a single bond a double bond a triple bond none of the above
Correct answer: a triple bond A triple bond forms when three electron pairs are shared by a pair of atoms.
What counts as an electron domain? Select the correct answer below: a single bond a double bond a lone pair all of the above
Correct answer: all of the above Any kind of bond, as well as a lone pair, will count as one electron domain.
What is a cation? Select the correct answer below: an atom that has lost electrons an atom that has gained electrons an atom with a neutral charge an atom with a negative charge
Correct answer: an atom that has lost electrons A cation is an atom that has lost electrons, and thus has a positive charge.
What is the molecular structure of O3? Select the correct answer below: tetrahedral trigonal planar bent trigonal pyramid
Correct answer: bent There are two resonance structures for O3, so the central O has two outer O's at equal length. The central O has one nonbonding pair so there are three electron domains, which means the electron-pair geometry is trigonal planar and the molecular structure is bent.
A molecule with three electron regions where one is a lone pair will have _____ molecular geometry. Select the correct answer below: tetrahedral trigonal planar bent or angular linear
Correct answer: bent or angular A molecule with three electron regions will have a trigonal planar electron geometry. If one of the domains is a lone pair, then it occupies one of the three locations around the central atom, and the molecular geometry will be bent or angular.
When the absolute value of the difference in electronegativity of two bonded atoms is very small or zero, the bond is: Select the correct answer below: ionic and polar covalent and polar ionic and nonpolar covalent and nonpolar
Correct answer: covalent and nonpolar When the absolute value of the difference in electronegativity of two bonded atoms is very small or zero, it means the two atoms have a very similar attraction to shared electrons. This means the bonds formed between the atoms are covalent and nonpolar. When the difference is large, the bond is polar covalent or ionic.
When drawing a Lewis structure, the first step is to: Select the correct answer below: draw a skeletal structure place lone pairs on the terminal atoms place electrons on the central atom determine the number of valence electrons
Correct answer: determine the number of valence electrons We must first determine the number of valence electrons in order to decide where they go.
The first step in predicting the geometry of a molecule is to: Select the correct answer below: count up the electron domains draw the Lewis structure count up the number of atoms measure the bond angles
Correct answer: draw the Lewis structure In order to assign geometry, we must know the number of electron domains around the central atom, and the only way to know the number of electron domains is to first draw the Lewis structure for the molecule.
VSEPR theory considers which of the following? Select the correct answer below: nuclear-electron attractions nuclear-nuclear repulsions electron-pair repulsions all of the above
Correct answer: electron-pair repulsions VSEPR theory considers electron-pair repulsions in that it predicts molecular structure based on electron pairs minimizing their repulsions from each other in order to achieve the most stable structure.
Which of the following describes how tightly an atom attracts electrons in a bond? Select the correct answer below: electronegativity ionization energy atomic radius electron affinity
Correct answer: electronegativity Electronegativity describes how tightly an atom attracts electrons in a bond. It determines how the shared electrons are distributed between the two atoms in covalent bond. The more strongly an atom attracts the electrons in its bonds, the larger its electronegativity.
Electronegativity is measured in: Select the correct answer below: kJmol kJg Ng electronegativity is dimensionless
Correct answer: electronegativity is dimensionless There are no units on electronegativity, it is an arbitrary relative scale designed by Linus Pauling.
Different ions of a given element will have differing numbers of __________. Select the correct answer below: protons neutrons electrons molecular formulas
Correct answer: electrons Ions and neutral atoms of the same element differ by having different numbers of electrons. For example, silver has both a +1 and a +2 cation with 46 and 45 electrons, respectively.
Use the periodic table below to answer the question that follows. Which of the following is the correct name for F−? Select the correct answer below: fluorion fluorine ion fluorine fluoride
Correct answer: fluoride The ion name for F− is fluoride. Simple anions are named by replacing the end of the element name with -ide.
The element with the highest electronegativity is: Select the correct answer below: helium neon carbon fluorine
Correct answer: fluorine In general, electronegativity increases from left to right across a period in the periodic table and decreases down a group. Thus, the nonmetals, which lie in the upper right, tend to have the highest electronegativities, with fluorine being the most electronegative element (EN=4.0).
When illustrating bond dipoles, vectors point from the ________ electronegative atom to the _______ electronegative atom. Select the correct answer below: more, less less, more both A and B neither A or B
Correct answer: less, more Vectors point from the less electronegative atom to the more electronegative atom. This is to indicate the direction of the bond dipole moment: the vector shows that the electrons are literally pulled toward the more electronegative atom.
What type of electron-pair geometry will CO2 exhibit? Select the correct answer below: linear bent trigonal planar tetrahedral
Correct answer: linear There are two bonds in CO2, and no lone pairs on the central atom. Two regions of electron density around a central atom in a molecule form a linear geometry that has 180∘ bond angles in order to make the domains as far from one another as possible.
Which of the following correctly pairs the ion name with the ion symbol?
Correct answer: lithium cation, Li+ The correct pairing of the monoatomic ion with its formula is lithium ion with Li+.
Use the periodic table below to answer the question that follows. MgSO3 is called ___________. Select the correct answer below: magnesium sulfate magnesium sulfide magnesium sulfur oxide magnesium sulfite
Correct answer: magnesium sulfite Because SO2−3 has one fewer oxygen than a sulfate ion, it is called a sulfite ion, hence magnesium sulfite.
Which of the following describes the location of atoms in a molecule? Select the correct answer below: molecular structure (molecular geometry) electron-pair geometries electron structures none of the above
Correct answer: molecular structure (molecular geometry) The molecular structure (also called molecular geometry or molecular shape) describes the arrangement of atoms in space around a central atom.
The Lewis symbol for phosphorus will have the same number of electrons as the Lewis symbol for: Select the correct answer below: oxygen nitrogen carbon neon
Correct answer: nitrogen Phosphorus and nitrogen both have five valence electrons, and thus have five dots on their Lewis symbols.
If an atom has a full octet, it will have: Select the correct answer below: a negative charge a positive charge noble gas electron configuration covalent bonds
Correct answer: noble gas electron configuration The atom may or may not have some formal charge and/or covalent bonds, but it certainly will have the electron configuration of the nearest noble gas.
Covalent bonds are formed most frequently between __________. Select the correct answer below: noble gases metalloids metals nonmetals
Correct answer: nonmetals Nonmetals are most likely to combine and form covalent bonds. Noble gases rarely form bonds since they already have 8 valence electrons. Metals commonly form either ionic or metallic bonds, depending on the type of element(s) with which they are bonding. Metalloids form covalent, ionic, and metallic bonds. However, it is not as common for this group to form covalent bonds.
The _______ is the tendency of main group elements to form enough bonds to obtain eight valence electrons. Select the correct answer below: electron deficient rule odd electron rule octet rule none of the above
Correct answer: octet rule The octet rule is the tendency of main group elements to form enough bonds to obtain eight valence electrons.
In an electric field, polar molecules align with the ______ toward the negative plate and the ______ toward the positive plate. Select the correct answer below: positive end, negative end negative, positive negative, negative none of the above
Correct answer: positive end, negative end Polar molecules have a separation of charges that has one atom more positive (less electronegative) than the other molecule (more negative, more electronegative). This separation allows polar molecules to align with opposite charges in electric fields. The more positive end of the molecule will align with the more negative plate, and the more negative end of the molecule will align with the more positive plate.
The R in VSEPR theory stands for Select the correct answer below: rotation. reduction. reaction. repulsion.
Correct answer: repulsion. It is the idea that regions of electron density will repel other regions of electron density that is at the center of VSEPR theory.
A molecule with four electron domains will exhibit which geometry according to VSEPR theory? Select the correct answer below: trigonal planar tetrahedral linear
Correct answer: tetrahedral Four electron domains surrounding a central atom will exhibit a tetrahedral geometry because for four electron domains to have the most stable orientation, their repulsions must be minimized, resulting in a tetrahedral arrangement with a bond angle of 109.5∘.
What is the molecular structure of SiH4? Select the correct answer below: bent tetrahedral trigonal pyramid trigonal planar
Correct answer: tetrahedral SiH4 has four regions of electron density, one for each bond between the central silicon atom and each of the four hydrogen atoms. Therefore, both the electron-pair geometry and molecular structure for SiH4 are tetrahedral.
What type of electron-pair geometry will CH4 exhibit? Select the correct answer below: linear bent trigonal planar tetrahedral
Correct answer: tetrahedral There are four bonds in CH4, and no lone pairs on the central atom. Four regions of electron density around a central atom in a molecule form a tetrahedral geometry that has 109.5∘ bond angles in order to make the domains as far from one another as possible.
The molecular structure of a molecule will differ from its electron-pair geometry if: Select the correct answer below: the central atom has no lone pairs the central atom has at least one lone pair the terminal atoms have no lone pairs each terminal atom has at least one lone pair
Correct answer: the central atom has at least one lone pair The molecular structure is determined by the number of lone pairs on the central atom.
Electronegativity increases _________ on the periodic table. Select the correct answer below: up and left up and right down and left down and right
Correct answer: up and right In general, electronegativity increases from left to right across a period in the periodic table and decreases down a group. Thus, the nonmetals, which lie in the upper right, tend to have the highest electronegativities, with fluorine being the most electronegative element (EN = 4.0).
The dots on a Lewis symbol represent: Select the correct answer below: core electrons valence electrons protons neutrons
Correct answer: valence electrons The dots represent the outermost electrons of an atom, which are the ones available for bonding.
In the PF5 molecule, what is the geometry of the bond dipole for one PF bond? Select the correct answer below: vector pointing toward F vector pointing toward P the dipole moment is 0 none of the above
Correct answer: vector pointing toward F The vector would begin over P and point toward F because F is the more electronegative atom.
Which of the following is the equation for bond dipole moment? Select the correct answer below: μ=Qr μ=Qr μ=Q+r μ=q−r3
Correct answer: μ=Qr We represent the bond dipole moment magnitude in formulas using the greek letter "mu." The bond dipole moment is given by the formula: μ=Qr where Q is the magnitude of the partial charges (which is determined by the difference in electronegativity), and r is the distance between the charges.
How many valence electrons does the amino acid alanine, C3H7NO2, have? Provide your answer below:
Correct answers: 36 The amino acid alanine has 36 valence electrons. The carbon atoms have 4 valence electrons each. The hydrogen atoms have 1 valence electron each. The nitrogen atom has 5 valence electrons, and the oxygen atoms have 6 valence electrons each. C3H7NO2:(3×4)+(7×1)+(1×5)+(2×6)=36 valence electrons The lewis structure is shown in the image below.
How many valence electrons does HF have? Provide your answer below:
Correct answers: 8 The hydrogen fluoride molecule has 8 valence electrons. The hydrogen atom has 1 valence electron and the fluorine atom has 7 valence electrons. HF:(1×1)+(1×7)=8 valence electrons
Use the periodic table to answer the question that follows. Enter the formula for the carbide ion.
Correct answers: c^4- The carbide ion is the anion of carbon. This is known because of the "-ide" suffix which denotes a nonmetal anion. The root of the name is "Car-" which identifies the anion as carbon. Locating carbon on the periodic table, it is a group 14 nonmetal which will have the tendency to gain 4 electrons to reach a noble gas configuration
The Lewis symbol for sodium will have how many dots? Report your answer as an integer (whole number) without any decimal places. Do not include units in your response.
Correct answers:1 As sodium has one valence electron, its Lewis symbol will have one dot.
How many valence electrons does the polyatomic ion nitrite, NO−2, have? Provide your answer below:
Correct answers:18 Nitrite has 18 valence electrons. The nitrogen atom has 5 valence electrons, and the oxygen atoms have 6 valence electrons each. However, there is a negative charge on the ion; thus, there is an extra electron that must be considered. NO−2:(1×5)+(2×6)+(1×e−)=18 valence electrons
The Lewis symbol for the chloride ion will have how many dots? Report your answer as an integer (whole number) without any decimal places. Do not include units in your response.
Correct answers:8 If a chlorine atom gains an electron to become the chloride ion, it will have 8 valence electrons and a full valence shell. This means its Lewis symbol will have 8 dots.
What is the chemical formula for the polyatomic ion Chlorate?
Correct answers:ClO_3^- The chlorate ion is an anion with the formula ClO−3. This is a polyatomic ion that must be memorized. Be careful not to confuse it with the chlorite ion which has the formula ClO−2.
Chromium(II) phosphate is formed from the Cr2+ cation and the PO3−4 anion. What is the correct formula for this compound?
Correct answers:Cr_3(PO_4)_2 An ionic compound must be electrically neutral, so it must have the same number of positive and negative charges. Three chromium ions, each with a charge of 2+, would give us six positive charges, while 2 phosphate ions, each with a charge of 3−, would give us six negative charges. Therefore, the formula is three chromium ions to two phosphate ions: Cr3(PO4)2.
Which of the following states the result of a sodium atom transferring an electron to a chloride atom? Select the correct answer below: The sodium atom becomes more stable but the chloride atom becomes less stable. The chloride atom becomes more stable but the sodium atom becomes less stable. Each atom ends up with a less stable electron arrangement. Each atom ends up with a more stable electron arrangement.
correct answer: Each atom ends up with a more stable electron arrangement. Each atom ends up with a more stable outer electron shell. The sodium atom transfers its 1 valence (outer shell) electron to the chloride atom. The chloride atom has 7 valence electrons so it only needs 1 more to be stable. So, the one electron that chlorine receives from sodium makes it more stable and now sodium, with the loss of the 1 electron, is more stable.
Atoms that form ions with a positive charge are known as __________. Select the correct answer below: neutrons protons anions cations
correct answer: cations Atoms that form ions with a positive charge are known as cations.
