Here are the correct responses to each question:
**Question 1**
A) The mass number of an atom is calculated by:
**Response**: **protons plus neutrons**
**Question 2**
A) Which atom would be neutral?
**Response**: **an oxygen atom with 8 electrons, 8 protons, and 9 neutrons**
(Note: An atom is neutral if it has an equal number of protons and electrons. The other options have a different number of protons and electrons.)
**Question 3**
A) A nitrogen ion has a mass of 14 and a charge of +2. Which subatomic particles does it contain?
**Response**: **7 protons, 7 neutrons, and 5 electrons**
(Explanation: A nitrogen atom has 7 protons and typically 7 neutrons, but since the charge is +2, it has lost 2 electrons.)
**Question 4**
A) Which option is an isotope with 6 protons and 8 neutrons?
**Response**: **carbon-14**
(Explanation: Carbon has 6 protons, and when it has 8 neutrons, its mass number becomes 14. The notation 'carbon-14' indicates this isotope.)