Question

date 10/6/25
atomic structure worksheet
period 4
list the 3 subatomic particles, their charges, masses and where in the atom they are located in the chart below:
subatomic particle electrical charge location in atom relative mass (amu)
protons
electrons
neutrons
describe how to determine the number of each subatomic particle in an atom below
proton: equal to atomic #
electron: equal to atomic #
neutron: mass - atomic #
fill in the chart for the elements below. round all atomic masses to the nearest whole number:
element symbol atomic number atomic mass # of protons # of electrons # of neutrons
sodium na 11 22.990 11 11 12
copper cu 29 63.546 29 29 30
chlorine cl 17 35.45 17 17 18
silver ag 47 107.87 47 47 48
lead pb 82 207.2 82 82 83
calcium ca 20 40.078 20 20 21
hafnium hf 72 178.49 72 72 73
radon rn 86 222 86 86 87
neptunium np 93 93 52
uranium u 92 238.03 92 92
potassium

Explanation:

Step1: Recall sub - atomic particle properties

Protons have a charge of +1, are located in the nucleus, and have a relative mass of approximately 1 amu. Electrons have a charge of - 1, are located outside the nucleus in orbitals, and have a relative mass of approximately 0 amu. Neutrons have a charge of 0, are located in the nucleus, and have a relative mass of approximately 1 amu.

Step2: Determine number of sub - atomic particles

The number of protons is equal to the atomic number of the element. In a neutral atom, the number of electrons is equal to the number of protons (equal to the atomic number). The number of neutrons is calculated as the atomic mass (rounded to the nearest whole number) minus the atomic number.

Step3: Fill in the element chart

For sodium (Na): Atomic number = 11, so number of protons = 11. Since it's neutral, number of electrons = 11. Atomic mass rounded to 23, number of neutrons = 23 - 11=12.
For copper (Cu): Atomic number = 29, number of protons = 29, number of electrons = 29, atomic mass rounded to 64, number of neutrons = 64 - 29 = 35.
For chlorine (Cl): Atomic number = 17, number of protons = 17, number of electrons = 17, atomic mass rounded to 35, number of neutrons = 35 - 17 = 18.
For silver (Ag): Atomic number = 47, number of protons = 47, number of electrons = 47, atomic mass rounded to 108, number of neutrons = 108 - 47 = 61.
For lead (Pb): Atomic number = 82, number of protons = 82, number of electrons = 82, atomic mass rounded to 207, number of neutrons = 207 - 82 = 125.
For calcium (Ca): Atomic number = 20, number of protons = 20, number of electrons = 20, atomic mass rounded to 40, number of neutrons = 40 - 20 = 20.
For hafnium (Hf): Atomic number = 72, number of protons = 72, number of electrons = 72, atomic mass rounded to 179, number of neutrons = 179 - 72 = 107.
For radon (Rn): Atomic number = 86, number of protons = 86, number of electrons = 86, atomic mass rounded to 222, number of neutrons = 222 - 86 = 136.
For neptunium (Np): Atomic number = 93, number of protons = 93, number of electrons = 93, atomic mass rounded to 237, number of neutrons = 237 - 93 = 144.
For uranium (U): Atomic number = 92, number of protons = 92, number of electrons = 92, atomic mass rounded to 238, number of neutrons = 238 - 92 = 146.
For potassium (K): Atomic number = 19, number of protons = 19, number of electrons = 19, atomic mass rounded to 39, number of neutrons = 39 - 19 = 20.

Answer:

Element	Symbol	Atomic Number	Atomic Mass (rounded)	# of Protons	# of Electrons	# of Neutrons
copper	Cu	29	64	29	29	35
chlorine	Cl	17	35	17	17	18
silver	Ag	47	108	47	47	61
lead	Pb	82	207	82	82	125
calcium	Ca	20	40	20	20	20
hafnium	Hf	72	179	72	72	107
radon	Rn	86	222	86	86	136
neptunium	Np	93	237	93	93	144
uranium	U	92	238	92	92	146
potassium	K	19	39	19	19	20