Question

1. the atomic number of an element whose atoms have 15 protons and 16 neutrons is

a. 16
c. 1
b. 15
d. 31

1. all atoms of the element have the same

c. mass numbers
a. number of neutrons
b. number of protons
d. number of electrons

1. balance the following equation:

⁴be + ⁴he → ¹²c +
⁴he
c. ¹h
a.
b. ⁰n
d. ⁰e

1. daltons atomic theory included which idea that was later proven incorrect?

a. atoms of the same element are always
c. atoms of different elements always
identical
combine in one - to - one ratios
b. individual atoms can be seen with a
d. all atoms of all elements are the same
microscope

1. the particles that are found in the nucleus of an atom are

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

1. according to dalton, elements can chemically combine in 1 - to - 1 ratios to form

c. compounds
a. isotopes
b. new elements
d. mixtures

1. the only subatomic particle that does not carry an electrical charge is the

c. electron
a. proton
b. neutron
d. nucleus

1. carbon - 12 and carbon - 14 are examples of

c. isotopes
a. nuclei
b. isomers
d. neutrons

1. using the periodic table, determine the number of neutrons in ²⁰ne

c. 10
a. 20
b. 30
d. 9

Explanation:

Step1: Answer question 8

The atomic number is equal to the number of protons. Given 15 protons, the atomic number is 15.

Step2: Answer question 9

All atoms of an element have the same number of protons.

Step3: Answer question 10

In a nuclear - reaction, mass number and atomic number are conserved. For \(^{9}_{4}Be+^{4}_{2}He
ightarrow^{12}_{6}C + ^{1}_{0}n\), the sum of mass numbers on the left (\(9 + 4=13\)) and on the right (\(12 + 1 = 13\)), and the sum of atomic numbers on the left (\(4+2 = 6\)) and on the right (\(6+0 = 6\)).

Step4: Answer question 11

Dalton's idea that atoms of the same element are always identical was later proven incorrect because of the existence of isotopes.

Step5: Answer question 12

Protons and neutrons are found in the nucleus of an atom.

Step6: Answer question 13

According to Dalton, elements can chemically combine in 1 - to - 1 ratios to form compounds.

Step7: Answer question 14

The only subatomic particle that does not carry an electrical charge is the neutron.

Step8: Answer question 15

Carbon - 12 and carbon - 14 are examples of isotopes (atoms of the same element with different numbers of neutrons).

Step9: Answer question 16

For \(^{20}Ne\), the mass number is 20 and the atomic number of Ne is 10. The number of neutrons \(=20 - 10=10\).

Answer:

1. b. 15
2. b. number of protons
3. b. \(^{1}_{0}n\)
4. a. Atoms of the same element are always identical
5. d. protons and neutrons
6. c. compounds
7. b. neutron
8. c. isotopes
9. c. 10