NAME:
CHEMISTRY REVIEW - PART 2
DATE:
BLOCK:
BACKGROUND:
1. Atoms want to achieve a full ________________________ and will __________________
electrons to do this.

very stable and have low energy states (ie: noble gases)
2. Cations are:
3. Anions are:
4. Atoms can also _________ electrons
5. There are two ways that ions can form compounds:
A.
B.
IONIC BONDING (IONIC COMPOUNDS)

Ionic compounds are formed usually between a _____________________ and a
_________________________

one or more electrons are _____________________ from the metal to the non-metal
Example #1: Sodium (Na) is a metal that can get a full valence shell by losing 1 electron and chlorine (Cl) is a nonmetal that can get a full valence shell by gaining 1 electron. They’re perfect for each other and they form sodium
chloride (NaCl)!
Mr. Culp
Chemistry
Science and Tech 11
Example #2:
Calcium fluoride (CaF2) is an ionic compounds formed from 1 atom of the metal calcium and 2 atoms of the
non-metal fluorine. The calcium atom transfers 2 electrons in total (1 electron to each of the fluorine atoms).
COVALENT BONDING (COVALENT COMPOUNDS)

covalent compounds/molecules are formed when two ____________________ atoms
_______________ electrons
(“CO” = together/share and “VALENT” = valence electrons  shared valence electrons)
o the term ‘___________________’ applies specifically to covalent compounds
o some common covalent compounds are water, methane, ammonia

_________________________:
o Each atom in a covalent molecule will share 1 valence electron
o Any pairs of valence electrons NOT shared are called _______________________.
Can you spot the bonding pairs and the lone pairs in the diagrams above?
Mr. Culp
Chemistry
Science and Tech 11

Some elements are more stable when paired as two atoms that share electrons. These
molecules are called _____________________________________.
o Elements that are diatomic are:
hydrogen (H2), nitrogen (N2), oxygen (O2), chlorine (Cl2), fluorine (F2), bromine (Br2), and
iodine (I2).
LEWIS DIAGRAMS

Lewis diagrams are great for illustrating chemical bonding because they show only the
________________ electrons of atoms
o A lot less work than drawing Bohr diagrams!
To draw a Lewis diagram, follow these steps:
1. figure out how many valence electrons an atom has
2. place 1 electron at a time starting at the North position until all electrons have been place
a. you may end up with paired and unpaired electrons
Mr. Culp
Chemistry
Science and Tech 11
To draw a Lewis diagram to illustrate ionic bonding:
1. find the electric charge of the element to know how many electrons it will gain or lose
2. the cation will have no valence electrons and the anion will have a full valance shell (a stable octet)
3. add square brackets around each atom (they tell us that electrons have been transferred)
4. include an ion charge to the top right hand corner of each square bracket
Example: Sodium chloride (NaCl)
Example: Barium bromide (BaBr2)
To draw a Lewis diagram to illustrate covalent bonding:
1. identify bonding pair (shared electrons)
2. draw a line to represent the bonding pair
Example: water (H2O)
Mr. Culp
Example: Methane (CH4)
Chemistry
Science and Tech 11