Question

multiple choice write the correct letter in the blank.

1. the atomic number of carbon is 6. therefore, the number of protons in a carbon atom equals

a. 3. b. 6. c. 7. d. 12.

1. one of the kinds of particles found in the nucleus of an atom is the

a. proton. b. electron. c. ion. d. boron.

1. the maximum number of electrons that can be held in an atoms second energy level is

a. 2. b. 4. c. 6. d. 8.

1. of the following elements, the one that is most likely to form ionic bonds is

a. hydrogen. b. carbon. c. sodium. d. oxygen.

1. an example of a compound is

a. water. b. hydrogen gas. c. oxygen gas. d. chloride ion.
modern biology study guide

Explanation:

1. The atomic number of an element is equal to the number of protons in its atom. Since the atomic number of carbon is 6, the number of protons is 6.
2. Protons and neutrons are found in the nucleus of an atom. Electrons are outside the nucleus. Ions are charged atoms or groups of atoms. Boron is an element, not a particle in the nucleus.
3. The formula for the maximum number of electrons in an energy level is \(2n^{2}\), where \(n\) is the energy level number. For the second energy level (\(n = 2\)), \(2\times2^{2}=8\).
4. Sodium is a metal and has a tendency to lose electrons to form ionic bonds. Hydrogen, carbon, and oxygen are more likely to form covalent bonds.
5. A compound is a substance formed when two or more elements are chemically bonded together. Water (\(H_{2}O\)) is a compound. Hydrogen gas (\(H_{2}\)) and oxygen gas (\(O_{2}\)) are elements. A chloride ion (\(Cl^{-}\)) is an ion, not a compound.

Answer:

1. B. 6
2. A. proton
3. D. 8
4. C. sodium
5. A. water