Which of the following is the atomic number of an atom that has 12 protons and 12 neutrons?

We find the number of neutrons as follows

Number of neutrons

= mass number – atomic number

= 207 – 82

= 125 neutrons

elements are arranged on the periodic table based on their atomic number. This identity is critical in evaluating the chemical families of elements in chemistry. Atoms are made of protons, neutrons, and electrons. Protons and neutrons are found in the nucleus while electrons are found outside the nucleus of the atom. It is the number of protons of an atom that gives its atomic number. Therefore, an atom with 12 protons has an atomic number of 12.

The atom is identified by the atomic number in the periodic table. The atomic number is equal to the number of protons and mass number is the sum of the number of protons and neutrons in the nucleus of an atom. Thus, to find how many neutrons are in lithium atom we use the formula below.

Mass number = number of protons + number of neutrons.

Letting n be number of neutrons in the lithium atom, we have

7=3+n

Rearranging the above equation

3+n=7

n=7-3

n=4

Thus, lithium atom has 4 neutrons.

Or (Other explanation)

To find the number of neutrons in a lithium atom, you subtract the atomic number (number of protons) from the mass number.

Given:
Atomic number of lithium (Z) = 3
Mass number (A) = 7

Number of neutrons (N) = Mass number (A) - Atomic number (Z)

So,
Number of neutrons = 7 - 3 = 4

Therefore, the correct answer is4

The Lewis structure of nitrogen gas is shown below. Triple bonds are stronger than double or single bonds. Therefore, we can infer that the triple bond between the two nitrogen atoms makes nitrogen gas more stable.