For calcium-42, How many protons, neutrons and electrons are present,
respectively.
A. 20, 42, 20
B. 20, 22, 20
C. 20, 22, 18
D. 42, 20, 20

B. 20, 22, 20

Explanation:

The atomic number (Z) of calcium is 20, that is, it has 20 protons.

The mass number (A) of calcium-42 is 42. The mass number is equal to the sum of protons and neutrons. Then,

p⁺ + n⁰ = 42

n⁰ = 42 - p⁺

n⁰ = 42 - 20

n⁰ = 22

Since calcium is electrically neutral, it has the same number of protons (+) and electrons (-). Then, calcium has 20 electrons.

can you attach a picture of the lettuce? : )

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.