bonding

Question 1

What is a chemical bond?

Answer 1

A force that holds atoms together

Question 2

Why do atoms form chemical bonds?

Answer 2

To become stable by reaching a full outer shell, usually of 2 or 8 electrons

Question 3

What is the octet rule?

Answer 3

Elements combine to fill their outermost shell. For a lot of elements, this means 8 electrons in the outermost shell.

Question 4

How is # of valence electrons determined for elements in Periods 1,2, or 13-18?

Answer 4

Look at them as being their own thing and ignore the transition metals and Lanthanides and Actinides. Then, they have the # of valence electrons relating to their period number
Period 1=1 valence
Period 2=2 valence
Period 13=3 valence
Period 14=4 valence

Question 5

Transition metals usually have ___ or ____ valence electrons, but some can have up to ____ or _____

Answer 5

2
3
5
6

Question 6

Which period has the most stable atoms?

Answer 6

Period 18

Question 7

What is an ionic bond? What kind of elements does it happen between?

Answer 7

A bond where one atom “gives away” an electron to another atom and a new bond is formed by the attraction between the ions
nonmetal and metal

Question 8

What is a covalent bond? What kind of element does it happen between?

Answer 8

Two atoms share electrons to reach their full outer state

nonmetals

Question 9

What is a metallic bond? What kind of element does it happen between?

Answer 9

atoms connected through a “sea of electrons”

metals

Question 10

What causes ionic bonds?

Answer 10

Electrostatic Attraction, or when two oppositely charged objects are attracted to each other (in this case, ions)

Question 11

What is a simple ion?

Answer 11

An ion formed from a single ion (ex: H+)

Question 12

What is a polyatomic ion?

Answer 12

An ion that is formed when two or more atoms join together (so in other words, a bunch of atoms that are ionically bonded makes up a polyatomic ion).
(ex: Ammonium with one atom nitrogen and 4 hydrogen atoms, or hydroxide with one atom oxygen and one atom hydrogen)

Question 13

Talk out loud and explain how calcium and oxygen bond to make CaO

Answer 13

Calcium wants to get rid of 2 electrons (is a metal, wants to get to a full outer shell)
Oxygen wants 2 electrons (is a nonmetal, wants to get a full outer shell)
Calcium gives electrons to Oxygen and then they become attracted to one another as Calcium gains a 2+ attraction and Oxygen gains a 2- attraction
2- and 2+ cancel out, so the two make CaO

Question 14

Talk out loud and explain how sodium, oxygen, and hydrogen bond to make NaOH

Answer 14

Oxygen and Hydrogen bond to make OH as Hydrogen only needs one more electron
Then Oxygen still needs one more electron even though it’s bonded with hydrogen, and Sodium has 1 extra electron that it can give oxygen.
So Sodium bonds with oxygen, which is already bonded to hydrogen, so altogether they make NaOH

Question 15

An ionic compound always has a net charge of ____. Why?

Answer 15

0

Because the positive charge of the cations will be equal to the negative charge of the anions.

Question 16

What are some properties of ionic compounds? (4)

Answer 16

• bond is hard to break (electrostatic attraction is strong)
• high melting point and high boiling point (opposite of covalent bond)
• hard and brittle
• salts (just means they are made from a nonmetal and metal) (exceptions are oxides which have a metal and an oxygen and hydroxides which have a metal and a hydrogen)

Question 17

How are ionic compounds arranged? How are the anions arranged? How are the cations arranged?

Answer 17

In a crystal lattice.
The anions line up in a sort of cubical shape with anions on the inside too.
Because nonmetal anions are bigger than metal cations, as the anions line up, the cations fit into the spaces within the anions
(look up a picture if confused)

Question 18

Can ionic bonds have more than one element?

Answer 18

Yes

Question 19

How do magnesium and chlorine form an ionic bond?

Answer 19

Chlorine needs one electron but magnesium needs to get rid of two. Hence, 2 chlorine atoms are needed to fulfill the requirements of one magnesium atom and together they form MgCl2

Question 20

What happens to ionic compounds in water?

Answer 20

They disassociate (break up into ions)
Once cations and anions are free to float around, they can conduct electricity

Question 21

Covalent bonding occurs mostly between nonmetals that are _____

Answer 21

close to each other on the periodic table (similar electronegativities)

Question 22

What are some properties of covalent compounds?

Answer 22

• low melting and boiling points (opposite of ionic bond)
• don’t conduct electricity
• don’t dissolve well in water
• more flammable than ionic compounds
• not as hard as ionic compounds

Question 23

What is a diatomic molecule?

Answer 23

A molecule where an atom has formed a covalent bond with itself to become more stable (ex: H2, O2)

Question 24

What is a double bond?

Answer 24

Appears when two atoms share 4 electrons

Question 25

What is a triple bond?

Answer 25

Appears when 3 atoms share 6 electrons

Question 26

What is the duet rule?

Answer 26

For Helium and hydrogen, a full outer shell is 2 electrons.

Question 27

How do some group 3 elements bond?

Answer 27

Settle for a covalent bond 3 valence electrons (ex: BH3 or Boron and 3 Hydrogen)