How many Protons And Neutrons in these isotopes?

(note that the mass # follows the name of the element)

Chromium-58

Chromium-63

Carbon-12

Carbon-16

Nitrogen-15

Nitrogen-20

Sodium-12

Sodium-20

Sulfur-23

Sulfur-25

1 Answer
Mar 27, 2018

See Below

Explanation:

Look up each element on the periodic table. The atomic number (usually the whole number....increases one after the other), is the number of protons. Carbon, for example, is atomic number 6. This means carbon has 6 protons.

Take the mass number for each element above and subtract the atomic number (number of protons). This will give you the number of neutrons.

For example, carbon on periodic table is atomic number 6. That means 6 protons. Above, it says Carbon-12. 12 is the mass number.
#"Mass number" - "Atomic number" = "neutrons"#
12-6 = 6 neutrons.
Carbon: 6 protons, 6 neutrons....and so on.

One more. Nitrogen-20
Nitrogen is atomic number 7. So it has 7 protons.
20-7 = 13 This isotope of nitrogen has 13 neutrons.