Take these on a separate sheet of paper. Then, compare your answers to the ones
at the bottom of this page.
Tell how many protons, neutrons, and electrons each element has based on the
Name these compounds.
a.) CuCl b.) NaF c.) MnO2 d.) FeBr2 e.) Fe2O3
Find the formula for each chemical below.
a.) Sodium sulfate b.) Vanadium (V) fluoride c.) Mercury
(I) chloride d.) Tin (II) fluoride e.) Cobalt (III) nitrate
- The atomic weight is 16 amu. Since we know that oxygen, with a 8, has 8 protons
(that is the definition of a an atomic number), we can then deduce that oxygen has 8
neutrons (16-8 = 8). Final answer? 8 protons, 8 electrons, and 8 neutrons. Please note
that in an elemental state, the number of electrons and protons will always be equal.
- With an atomic weight of 11 amu, along with an atomic number of six, boron has
5 neutrons. (11 amu - 6 protons = 5 neutrons)
- 4 protons, 4 electrons, and 5 neutrons
- 3 protons, 3 electrons, and 4 neutrons
- 11 protons, 11 electrons, 12 neutrons
- By the rules, this is Copper Chloride. But copper can have different charges, so you
must figure what the charge on this one is. Let's see: you know chloride can have only one
value, and that's a -1. So if they must add up to zero, Cu must be +1. The answer is
copper (I) chloride.
- This is sodium and fluorine, so the name is sodium fluoride. Sodium can only be +1, so
there is no need for roman numerals.
- The name is Manganese Oxide, but a roman numeral is necessary, since it's a transition
metal. In this case, manganese is a transition metal, so it needs a roman numeral. Let's
start with oxygen: Each oxide ion has a charge of -2, and there are 2 of them. So the
total charge due to oxide is -4. The single manganese ion must compensate for this, so its
charge must be +4. The name is manganese (IV) oxide.
- Same here. It needs a roman numeral. Br is -1, and 2 of them, so Fe must be +2. Name is
Iron (II) Bromide.
- e.This one's a little bit different, but the same concepts apply. You start with the
oxygens. 3 of -2 ions make it a total of -6 charge due to oxide. So the two irons must
compensate. If two of them must equal +6, each must be...+3!!! It should be no surprise.
So the name of this is Iron (III) Oxide.
The ions are Na+ and SO42-. But Na has only +1, and SO4
is -2. So you need two Na's to make up for that -2. The answer is Na2SO4.
The ions are V5+ and F-. You know the +5 of vanadium by the (V).
So you need 5 fluorines to make up for that +5. The answer is VF5.
Mercury is the weird ion. Since it's (I), then the ion must be Hg22+.
And since there is a +2, you need two Cl-'s to balance. The answer is Hg2Cl2.
Tin is +2, so you need 2 F's to balance. Answer is SnF2.
Cobalt is +3, and nitrate is -1. Need three nitrates to balance, so answer is Co(NO3)3.