Question

protons, neutrons, and electrons practice worksheet
calculating the number of each particle in an atom:

protons = atomic number

electrons = protons

neutrons = atomic mass - atomic number or big # - small #

8
o
oxygen
15.999
use the periodic table to find the numbers of protons, neutrons, and electrons for atoms of the following elements.
name of element element symbol mass number atomic number protons neutrons electrons
boron b 11 5 5 6 5
sodium 24 11 11 13 11
y 89 39
copper 29 35
tc 98 43
pb 207
thallium 204 81
h 0
carbon 12
n 7
ba 56
calcium
si 14
argon 18
mg 12 12

Explanation:

Step1: Recall the rules

Number of protons = Atomic number. Number of electrons = Number of protons. Number of neutrons = Mass number - Atomic number.

Step2: For Yttrium (Y)

Atomic number of Y is 39. So, # Protons = 39, # Electrons = 39, # Neutrons = 89 - 39=50.

Step3: For Copper (Cu)

Atomic number of Cu is 29. So, # Protons = 29, # Electrons = 29, # Neutrons = 64 - 29 = 35 (assuming common - isotope with mass number 64).

Step4: For Technetium (Tc)

Atomic number of Tc is 43. So, # Protons = 43, # Electrons = 43, # Neutrons = 98 - 43 = 55.

Step5: For Lead (Pb)

Atomic number of Pb is 82. So, # Protons = 82, # Electrons = 82, # Neutrons = 207 - 82 = 125.

Step6: For Thallium (Tl)

Atomic number of Tl is 81. So, # Protons = 81, # Electrons = 81, # Neutrons = 204 - 81 = 123.

Step7: For Hydrogen (H)

Atomic number of H is 1. So, # Protons = 1, # Electrons = 1, # Neutrons = 1 - 1 = 0 (for common - isotope protium).

Step8: For Carbon (C)

Atomic number of C is 6. So, # Protons = 6, # Electrons = 6, # Neutrons = 12 - 6 = 6 (for common - isotope).

Step9: For Nitrogen (N)

Atomic number of N is 7. So, # Protons = 7, # Electrons = 7, # Neutrons = 14 - 7 = 7 (for common - isotope).

Step10: For Barium (Ba)

Atomic number of Ba is 56. So, # Protons = 56, # Electrons = 56, # Neutrons = 137 - 56 = 81 (assuming common - isotope).

Step11: For Calcium (Ca)

Atomic number of Ca is 20. So, # Protons = 20, # Electrons = 20, # Neutrons = 40 - 20 = 20 (assuming common - isotope).

Step12: For Silicon (Si)

Atomic number of Si is 14. So, # Protons = 14, # Electrons = 14, # Neutrons = 28 - 14 = 14 (assuming common - isotope).

Step13: For Argon (Ar)

Atomic number of Ar is 18. So, # Protons = 18, # Electrons = 18, # Neutrons = 40 - 18 = 22 (assuming common - isotope).

Step14: For Magnesium (Mg)

Atomic number of Mg is 12. So, # Protons = 12, # Electrons = 12, # Neutrons = 24 - 12 = 12 (assuming common - isotope).

Answer:

Name of Element	Element Symbol	Mass Number	Atomic Number	Protons	Neutrons	Electrons
Copper	Cu	64 (assumed)	29	29	35	29
Technetium	Tc	98	43	43	55	43
Lead	Pb	207	82	82	125	82
Thallium	Tl	204	81	81	123	81
Hydrogen	H	1	1	1	0	1
Carbon	C	12	6	6	6	6
Nitrogen	N	14	7	7	7	7
Barium	Ba	137 (assumed)	56	56	81	56
Calcium	Ca	40	20	20	20	20
Silicon	Si	28	14	14	14	14
Argon	Ar	40	18	18	22	18
Magnesium	Mg	24	12	12	12	12