Question

potassium contains 20 neutrons. how many electrons does it contain?
39
20
19
21
which type of macromolecule has the function of storing and transmitting hereditary or genetic information?
nucleic acid
protein
carbohydrate
lipid

Explanation:

Step1: Recall atomic number of potassium

The atomic number of potassium (\(K\)) is \(19\). For a neutral atom, the number of electrons equals the number of protons. The atomic number is equal to the number of protons.

Step2: Determine number of electrons

Since potassium is neutral and atomic number \(Z = 19\) (number of protons \(p=19\)), the number of electrons \(e=p = 19\).

For the second question:

Nucleic acids (such as DNA and RNA) are responsible for storing and transmitting hereditary or genetic information. Proteins have functions like catalysis (enzymes), structural support, etc. Carbohydrates are a source of energy (e.g., glucose) and can also have structural roles (e.g., cellulose). Lipids are used for energy storage (fats), as components of cell membranes (phospholipids) etc.

Answer:

For the first question: 19
For the second question: nucleic acid