Question

mg
24.305
atomic # =
atomic mass =

of protons =

of neutrons =

of electrons =

18
argon
39.948
atomic # =
atomic mass =

of protons =

of neutrons =

of electrons =

19
k
39.098
atomic # =
atomic mass =

of protons =

of neutrons =

of electrons =

79
gold
196.967
atomic # =
atomic mass =

of protons =

of neutrons =

of electrons =

1
h
1.008
atomic # =
atomic mass =

of protons =

of neutrons =

of electrons =

9
fluorine
18.998
atomic # =
atomic mass =

of protons =

of neutrons =

of electrons =

Explanation:

Step1: Recall atomic - related concepts

The atomic number ($Z$) is equal to the number of protons. In a neutral atom, the number of electrons is equal to the number of protons. The number of neutrons ($N$) can be calculated as $N = \text{Atomic Mass}-\text{Atomic Number}$ (rounded to the nearest whole - number for simplicity).

For Mg (Magnesium):

• Atomic number ($Z$) is 12 (from the periodic table).
• Atomic Mass is 24.305.
• Number of Protons = 12 (since Atomic number = number of protons).
• Number of Neutrons $\approx24 - 12=12$ (rounding 24.305 to 24).
• Number of Electrons = 12 (for a neutral atom, number of electrons = number of protons).

For Ar (Argon):

• Atomic number ($Z$) is 18.
• Atomic Mass is 39.948.
• Number of Protons = 18.
• Number of Neutrons $\approx40 - 18 = 22$ (rounding 39.948 to 40).
• Number of Electrons = 18.

For K (Potassium):

• Atomic number ($Z$) is 19.
• Atomic Mass is 39.098.
• Number of Protons = 19.
• Number of Neutrons $\approx39 - 19=20$ (rounding 39.098 to 39).
• Number of Electrons = 19.

For Au (Gold):

• Atomic number ($Z$) is 79.
• Atomic Mass is 196.967.
• Number of Protons = 79.
• Number of Neutrons $\approx197 - 79 = 118$ (rounding 196.967 to 197).
• Number of Electrons = 79.

For H (Hydrogen):

• Atomic number ($Z$) is 1.
• Atomic Mass is 1.008.
• Number of Protons = 1.
• Number of Neutrons $\approx1 - 1=0$ (rounding 1.008 to 1).
• Number of Electrons = 1.

For F (Fluorine):

• Atomic number ($Z$) is 9.
• Atomic Mass is 18.998.
• Number of Protons = 9.
• Number of Neutrons $\approx19 - 9 = 10$ (rounding 18.998 to 19).
• Number of Electrons = 9.

Answer:

Element	Atomic Number	Atomic Mass	# of Protons	# of Neutrons	# of Electrons
Ar	18	39.948	18	22	18
K	19	39.098	19	20	19
Au	79	196.967	79	118	79
H	1	1.008	1	0	1
F	9	18.998	9	10	9