Question

part 1 multiple choice: write the answer that best answers the question in the blank. (2 pts each)

1. what is an atoms nucleus made of?

a. protons and electrons
c. protons and neutrons
b. protons only
d. neutrons only

1. the farther an electron is from the nucleus, the more ______ it has.

a. charge
b. energy
c. mass
d. size

1. atoms of the same element that have different numbers of neutrons are called

a. molecules
b. ions
c. protons
d. isotopes

1. which particles determine the atomic number of an element?

a. protons only
c. neutrons only
b. neutrons and protons
d. protons and electrons

1. how many electrons will a neutral atom of carbon have if its nucleus has 6 protons and 8 neutrons?

a. 2
b. 6
c. 8
d. 14

1. an element with 5 protons, 6 neutrons, and 8 electrons has an atomic number of

a. 5
b. 6
c. 8
d. 11

1. the total number of neutrons in the nucleus of any atom is equal to the

a. mass number of the atom
c. atomic number minus the mass number
b. atomic number of the atom
d. mass number minus the atomic number

1. two different isotopes of an element have different ______

a. numbers of neutrons
c. atomic numbers
b. numbers of protons
d. nothing is different about them

1. which of the following is a transition metal?

a. calcium
b. nickel
c. aluminum
d. tellurium

1. what is the correct symbol for an isotope of carbon with 6 protons and 6 neutrons?

a. carbon - 11
b. carbon - 12
c. carbon - 13
d. carbon - 14

1. boron, carbon, nitrogen and oxygen are all members of the same ______

a. family
c. group
b. period
d. valence level

1. which of the following elements would be the best conductor of electricity?

a. iodine
b. silicon
c. silver
d. argon

1. which of the following elements would be the most reactive?

a. iodine
b. silicon
c. silver
d. argon

1. which of the following elements would have one valence electron?

a. potassium
b. sodium
c. oxygen
d. phosphorus

1. which of the following elements would have two valence electrons?

a. potassium
b. sodium
c. oxygen
d. phosphorus

Explanation:

1. The nucleus of an atom consists of protons and neutrons.
2. Electrons farther from the nucleus occupy higher energy levels.
3. Isotopes are atoms of the same element with different neutron counts.
4. Atomic number is defined by the number of protons.
5. Neutral atoms have equal protons and electrons (6 protons = 6 electrons).
6. Atomic number equals the number of protons (5 protons).
7. Neutron count = mass number (protons + neutrons) - atomic number (protons).
8. Isotopes differ in neutron numbers (same proton count).
9. Nickel is a transition metal (groups 3-12); others are not.
10. Carbon-12 has 6 protons + 6 neutrons (mass number 12).
11. Boron, carbon, nitrogen, oxygen are in period 2 (same row).
12. Silver is a metal, the best conductor among the options.
13. Iodine (a halogen) is more reactive than the others.
14. Potassium (group 1) has 1 valence electron.
15. Magnesium (group 2) has 2 valence electrons.

Answer:

1. C. protons and neutrons
2. B. energy
3. D. isotopes
4. A. Protons only
5. B. 6
6. A. 5
7. D. mass number minus the atomic number
8. A. numbers of neutrons
9. B. Nickel
10. B. Carbon-12
11. B. Period
12. C. Silver
13. A. Iodine
14. A. Potassium
15. B. Magnesium