1.

Question

(03.01 MC)

An atom with 7 protons, 6 neutrons, and 7 electrons has an atomic mass of
amu. (Enter a whole number.) (3 points)
2.
(03.01 LC)

There are more electrons than protons in a negatively charged atom. (2 points)

True

False
3.
(03.01 LC)

Match the scientist with his discovery or contribution. (4 points)
1.
Ernest Rutherford
2.
John Dalton
3.
James Chadwick
4.
J. J. Thomson
a.
Electrons
b.
Atoms
c.
Protons
d.
Neutrons
4.
(03.01 LC)

Which contribution added to Rutherford's discovery of a positive nucleus? (3 points)

Atoms are indivisible.

Electrons are scattered in an atom.

Neutrons are inside the nucleus of an atom.

Atoms of the same element have the same properties.
5.
(03.01 LC)

A neutral atom of helium has 2 protons and
electrons. (Enter a whole number.) (2 points)

6.
(03.01 MC)

Which of the following elements has the highest combined number of protons and neutrons? (3 points)

Hydrogen: 1 amu

Nitrogen: 14 amu

Oxygen: 16 amu

Boron: 10 amu
7.
(03.01 MC)

Which of the following statements does not describe the structure of an atom? (3 points)

Inside the nucleus of an atom are protons and neutrons.

Protons are positively charged sub-atomic particles.

Electrons are negatively charged sub-atomic particles.

Most of the mass of an atom comes from the electron cloud.

Answer 1

Here are the answers to each question based on the information provided:

1. Atomic mass of the atom with 7 protons and 6 neutrons: The atomic mass can be approximated by adding the number of protons and neutrons. \[ \text{Atomic mass} = \text{Protons} + \text{Neutrons} = 7 + 6 = 13 , \text{amu} \]

2. There are more electrons than protons in a negatively charged atom.

   • Answer: True (Negatively charged atoms are called anions, which have more electrons than protons.)

3. Match the scientist with his discovery or contribution:

   • 1. Ernest Rutherford - c. Protons
   • 2. John Dalton - b. Atoms
   • 3. James Chadwick - d. Neutrons
   • 4. J. J. Thomson - a. Electrons

4. Which contribution added to Rutherford's discovery of a positive nucleus?

   • Answer: Neutrons are inside the nucleus of an atom. (This contributed to understanding the complete structure of the nucleus.)

5. A neutral atom of helium has 2 protons and

   • Answer: 2 electrons (It is neutral, so the number of protons equals the number of electrons.)

6. Which of the following elements has the highest combined number of protons and neutrons?

   • Hydrogen: 1 amu → 1 proton, 0 neutrons = 1 total
   • Nitrogen: 14 amu → 7 protons, 7 neutrons = 14 total
   • Oxygen: 16 amu → 8 protons, 8 neutrons = 16 total
   • Boron: 10 amu → 5 protons, 5 neutrons = 10 total
   • Answer: Oxygen (16 total protons and neutrons)

7. Which of the following statements does not describe the structure of an atom?

   • Answer: Most of the mass of an atom comes from the electron cloud. (Most of the mass of an atom comes from the nucleus, which contains protons and neutrons.)

I hope this helps! Let me know if you have any further questions.