CHEM 101 ACTUAL EXAM
QUESTIONS AND COMPLETE STUDY
GUIDE 2026
▶ charge of neutron. Answer: no charge, mass= 1 amu
▶ charge of electron. Answer: -1 charge, mass= 0 amu
▶ electron model. Answer: old model: orbiting electrons
new model: electron cloud (contains all electrons)
▶ nucleus. Answer: all the protons and neutrons
small volume
contains most of mass
▶a
X atomic symbol
z. Answer: a = mass number (p+n)
z = atomic number (p), *a-z=neutrons*
▶6
C periodic table
12.01. Answer: 6 = atomic number (periodic table arranged by this)
12.01 = average atomic mass
▶ elements are neutral. Answer: number of protons = number of electrons
▶ isotopes. Answer: Atoms with the same number of protons but different
numbers of neutrons
Properties determined by # of protons
▶ ions. Answer: atoms with a charge
-caused by different number of electrons
(-) = anion (electrons actually missing but taking away negative so # will go
up)
, (+) = cation (CATion = PAWsitive) (electrons actually gained but is adding
a negative so # will go down)
▶ How many electrons in O^-2. Answer: 8
O two more e- = 10e-
16
▶ How many e- in sodium?. Answer: 11 <-- 11 protons, 11 electrons if
neutral
Na
22.99
Na has a +1 charge on periodic table, so = 10e-
▶ electron shells. Answer: n=3 18e-
n= 2 8e-
n = 1 2e-
go from bottom up
highest up shell = valence electrons
▶ ionic compounds. Answer: cations and anions (pos and neg)
written Cation Anion
ex: write the formula for salt made of calcium + F
= Ca^+2 F^-1 so CaF2 (need to balance charges)
formed by metals + nonmetals
▶ ionic bond. Answer: between + and - charge
▶ covalent bond. Answer: between non metals
atom bonded to another atom of the same type
share electrons in order to get to 8 valence e- (except H and He get 2)
▶ naming covalent compounds. Answer: prefix: 1 mono, 2 di, 3 tri, 4 tetra,
5 penta, 6 hexa, 7 hepta, 8 octa, 9 nona, 10 deca
ending in "ide"
▶ transition metals. Answer: always + but some elements can have
multiple charges
QUESTIONS AND COMPLETE STUDY
GUIDE 2026
▶ charge of neutron. Answer: no charge, mass= 1 amu
▶ charge of electron. Answer: -1 charge, mass= 0 amu
▶ electron model. Answer: old model: orbiting electrons
new model: electron cloud (contains all electrons)
▶ nucleus. Answer: all the protons and neutrons
small volume
contains most of mass
▶a
X atomic symbol
z. Answer: a = mass number (p+n)
z = atomic number (p), *a-z=neutrons*
▶6
C periodic table
12.01. Answer: 6 = atomic number (periodic table arranged by this)
12.01 = average atomic mass
▶ elements are neutral. Answer: number of protons = number of electrons
▶ isotopes. Answer: Atoms with the same number of protons but different
numbers of neutrons
Properties determined by # of protons
▶ ions. Answer: atoms with a charge
-caused by different number of electrons
(-) = anion (electrons actually missing but taking away negative so # will go
up)
, (+) = cation (CATion = PAWsitive) (electrons actually gained but is adding
a negative so # will go down)
▶ How many electrons in O^-2. Answer: 8
O two more e- = 10e-
16
▶ How many e- in sodium?. Answer: 11 <-- 11 protons, 11 electrons if
neutral
Na
22.99
Na has a +1 charge on periodic table, so = 10e-
▶ electron shells. Answer: n=3 18e-
n= 2 8e-
n = 1 2e-
go from bottom up
highest up shell = valence electrons
▶ ionic compounds. Answer: cations and anions (pos and neg)
written Cation Anion
ex: write the formula for salt made of calcium + F
= Ca^+2 F^-1 so CaF2 (need to balance charges)
formed by metals + nonmetals
▶ ionic bond. Answer: between + and - charge
▶ covalent bond. Answer: between non metals
atom bonded to another atom of the same type
share electrons in order to get to 8 valence e- (except H and He get 2)
▶ naming covalent compounds. Answer: prefix: 1 mono, 2 di, 3 tri, 4 tetra,
5 penta, 6 hexa, 7 hepta, 8 octa, 9 nona, 10 deca
ending in "ide"
▶ transition metals. Answer: always + but some elements can have
multiple charges
