Question

fill in the blanks in the following worksheet. please keep in mind that the isotope represented by each space may not be the most common isotope or the one closest in atomic mass to the value on the periodic table.

atomic symbol	atomic number	protons	neutrons	electrons	atomic mass
na	11	11	13	11	24
		31	37
				39	89
	29		35
		43			100
pb					207
		102	70
		89			225
mo			53
	81				206
	100		159
no					261
yb					172
	106	159

Explanation:

Step1: Recall atomic number property

The atomic number is equal to the number of protons and for a neutral atom, the number of electrons. So for each row, if the atomic number is given, the number of protons and electrons (for neutral atoms) is the same as the atomic number.

Step2: Use atomic - mass formula

Atomic mass = number of protons+number of neutrons. So, number of neutrons = atomic mass - number of protons and atomic mass can be calculated as the sum of protons and neutrons.

For the row with atomic number 11:

• Atomic symbol: Na (since atomic number 11 corresponds to sodium)
• Protons = 11 (equal to atomic number)
• Neutrons = 13 (given)
• Electrons = 11 (for neutral atom, equal to protons)
• Atomic mass = 11 + 13=24

For the row with 31 protons:

• Atomic number = 31 (equal to number of protons)
• Atomic symbol: Ga (gallium has atomic number 31)
• Neutrons = 37 (given)
• Electrons = 31 (for neutral atom)
• Atomic mass = 31+37 = 68

For the row with 39 electrons:

• Protons = 39 (for neutral atom, equal to electrons)
• Atomic number = 39
• Atomic symbol: Y (yttrium has atomic number 39)
• Neutrons = 89 - 39=50
• Atomic mass = 89

For the row with atomic number 29:

• Atomic symbol: Cu (copper has atomic number 29)
• Protons = 29
• Neutrons = 35 (given)
• Electrons = 29
• Atomic mass = 29 + 35=64

For the row with 43 protons:

• Atomic number = 43
• Atomic symbol: Tc (technetium has atomic number 43)
• Neutrons = 100 - 43 = 57
• Electrons = 43
• Atomic mass = 100

For the row with Pb:

• Atomic number = 82 (lead has atomic number 82)
• Protons = 82
• Neutrons = 207 - 82=125
• Electrons = 82
• Atomic mass = 207

For the row with 70 electrons:

• Protons = 70 (for neutral atom)
• Atomic number = 70
• Atomic symbol: Yb (ytterbium has atomic number 70)
• Neutrons = 102 (given)
• Atomic mass = 70+102 = 172

For the row with 89 protons:

• Atomic number = 89
• Atomic symbol: Ac (actinium has atomic number 89)
• Neutrons = 225 - 89=136
• Electrons = 89
• Atomic mass = 225

For the row with Mo:

• Atomic number = 42 (molybdenum has atomic number 42)
• Protons = 42
• Neutrons = 53 (given)
• Electrons = 42
• Atomic mass = 42+53 = 95

For the row with atomic number 81:

• Atomic symbol: Tl (thallium has atomic number 81)
• Protons = 81
• Neutrons = 206 - 81=125
• Electrons = 81
• Atomic mass = 206

For the row with 100 protons:

• Atomic number = 100
• Atomic symbol: Fm (fermium has atomic number 100)
• Neutrons = 159 (given)
• Electrons = 100
• Atomic mass = 100+159 = 259

For the row with No:

• Atomic number = 102 (nobelium has atomic number 102)
• Protons = 102
• Neutrons = 261 - 102=159
• Electrons = 102
• Atomic mass = 261

For the row with Yb:

• Atomic number = 70
• Protons = 70
• Neutrons = 172 - 70 = 102
• Electrons = 70
• Atomic mass = 172

For the row with 106 protons:

• Atomic number = 106
• Atomic symbol: Sg (seaborgium has atomic number 106)
• Neutrons = 159 (given)
• Electrons = 106
• Atomic mass = 106+159 = 265

Answer:

Atomic symbol	Atomic number	Protons	Neutrons	Electrons	Atomic mass
Na	11	11	13	11	24
Ga	31	31	37	31	68
Y	39	39	50	39	89
Cu	29	29	35	29	64
Tc	43	43	57	43	100
Pb	82	82	125	82	207
Yb	70	70	102	70	172
Ac	89	89	136	89	225
Mo	42	42	53	42	95
Tl	81	81	125	81	206
Fm	100	100	159	100	259
No	102	102	159	102	261
Yb	70	70	102	70	172
Sg	106	106	159	106	265