Ch. 6 Science 9

What two types of elements does a metallic bond form between?

A metallic bond forms between two metals.

What are ions held together by?

Ions are held together by chemical bonds.

The compound ____ is an example of an ionic compound. a) H2O b) CO2 c) KCl d) PCl3

c) KCl

What are the characteristics for a metallic bond?

- Metals are flexible and conduct electric current well (when they are solid) because their atoms and electrons can move freely throughout a metal's packed structure. - Electrons move freely between metal atoms. - The atoms in metals form metallic bonds, which is a bond formed by the attraction between positively charged metal ions and the electrons around them. - The attraction between an atom's nucleus and a neighboring atom's electrons packs the atoms together, which causes the outermost energy levels of the atoms to overlap.

What are the characteristics for an ionic bond?

- The result is a positive and a negative ion. - Two atoms tend to form an ionic bond when one atom has more attraction for electrons than the other. - Ionic bonds are formed by the transfer of electrons. - Ionic compounds are in the form of networks, not molecules. - One Na+ ion and one Cl- ion make up a formula unit of NaCl. - When melted or dissolved in water, ionic compounds conduct electricity since the ions are then free to move. - Solid ionic compounds do not conduct electric current since the charged ions are locked into place. - Ionic compounds are solid at room temperature. - The melting and boiling points are generally high. - Formed between a non-metal and metal.

What type of bond forms between a tight network of oppositely charged ions?

An ionic bond forms between a tight network of oppositely charged ions.

What do we call a bond where atoms transfer electrons?

An ionic bond.

What is the 'magic' number of valence electrons an atom wants?

The magic number is 8.

Metallic bond

a bond formed by the attraction between positively charged metal ions and the electrons around them

Covalent bond

a bond formed when atoms share one or more pairs of electrons

A chemical bond can be defined as a force that... a) Holds the parts of an atom together. b) Joins atoms in a compound. c) Causes electric repulsion. d) Blends nuclei together.

a) Holds the parts of an atom together.

Chemical bond

the attractive force that holds atoms or ions together

What are the characteristics for a covalent bond?

- The structure is made up of molecules. - Compounds that are networks of bonded atoms are also covalently bonded. Valence electrons are shared. - Formed between two non-metal atoms. - Covalent compounds can be solids, liquids, or gases. - Most covalent compounds are made of molecules that have low melting points - usually below 300 degree Celcius. - Molecules are free to move when it is dissolved or melted, but these molecules are not charged, not allowing it to conduct electricity. - Atoms may share more than one pair of electrons. More energy is needed to break a triple bond than to break a double bond. Triple and double bonds are shorter than single bonds. - Atoms do not always share electrons equally. - Bonds in which electrons are shared equally are called nonpolar covalent bonds. - Bonds in which there is an unequal sharing of electrons are called polar covalent bonds. When two atoms of different elements share electrons, the electrons are not shared equally. - Melting and boiling points are generally low.

Steps for bonding covalent bonds

1) Determine the # of valence electrons for each element. 2) Decide which one needs more bonds (more electrons to become full). Draw the Lewis dot structure for this element (element #1) in the center. 3) Create a bond for each unpaired electrons in element #1. - Drawing the dot structure for element #2 next to the unpaired electrons. - Remember to include all electrons that the element had originally. - Circle element #2 if it now has a full outer shell. Step 4) Continue adding bonds until element #1 has a full outer shell and circle element #1. Step 5) Write the chemical formula.

Steps for bonding ionic bonds

1) Determine the # of valence electrons for each element. 2) Determine the charge of each element. 3) Draw the dot diagram for the non-metal (anion) in the center. 4) Create a bond for each unpaired electron. - Draw a Lewis dot structure for the metal (cation) - use X's instead of the dots. - Draw an arrow to show the transferring of electrons. *Continue adding bonds until element #1 has a full outer shell and element #2 has no valence electrons left. 5) Check that charges cancel. 6) Write the formula.

A classmate claims that sodium gains a positive charge when it becomes an ion because it gains a proton. Explain what is wrong with the student's claim.

A classmate claims that sodium gains a positive charge when it becomes an ion because it gains a proton. Explain what is wrong with the student's claim.

What two types of elements does a covalent bond form between?

A covalent bond forms between two non-metals.

What do we call a bond where atoms share electrons?

A covalent bond.

What is an ion? What are the two different types of ions and what are their charges?

An ion is an atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge. The two different types of ions are

What two types of elements does an ionic bond form between?

An ionic bond forms between a non-metal and a metal.

Why do atoms join or bond together?

Atoms join or form bonds so that each atom has a stable electron configuration.

Noble gases, such as helium and neon, have full, stable, outerlevel electron configurations. How does this fact explain why atoms of noble gases usually do not form chemical bonds?

Atoms of noble gases usually don't form chemical bonds because their full, stable, outerlevel electron configuration is happy. They don't usually bond because they would have an unstable level again.

A compound is different from a mixture because... a) A compound is held together by chemical bonds. b) Each substance in a compound maintains its own properties. c) Each original substance in a compound remains chemically unchanged. d) A mixture is held together by chemical bonds.

a) A compound is held together by chemical bonds.

Ions

an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons.

Ionic solids... a) Are formed by networks of ions that have the same charge. b) Melt at very low temperatures. c) Have very regular structures. d) Are sometimes found as gases at room temperature.

c) Have very regular structures.

Ionic bond

the attractive force between oppositely charged ions, which form when electrons are transferred from one atom to another