OCR A Level chemistry Module 2 and 3

Which of the following correctly describes the properties of protons, neutrons, and electrons in terms of relative mass, relative charge, and location in the atom?

• Protons: relative mass 1, relative charge +1, located in the nucleus; Neutrons: relative mass 1, relative charge 0, located in the nucleus; Electrons: relative mass 1/1836, relative charge -1, located in the electron cloud

• Protons: relative mass 1, relative charge 0, located in the nucleus; Neutrons: relative mass 1, relative charge +1, located in the nucleus; Electrons: relative mass 1/1836, relative charge -1, located in the electron cloud

• Protons: relative mass 1, relative charge +1, located in the electron cloud; Neutrons: relative mass 1, relative charge 0, located in the nucleus; Electrons: relative mass 1/1836, relative charge -1, located in the nucleus

• Protons: relative mass 1, relative charge +1, located in the nucleus; Neutrons: relative mass 1, relative charge 0, located in the electron cloud; Electrons: relative mass 1/1836, relative charge -1, located in the nucleus

The periodic table lists the elements in order of what?

• Atomic number

• Alphabetical order

• Date of discovery

• Atomic mass

Isotopes are atoms of the same element with different numbers of what?

• Protons

• Neutrons

• Electrons

• Photons

Isotopes can be represented by:

• Their atomic number and mass number

• Their chemical symbol and atomic number

• Their mass number and chemical symbol

• Their atomic number and electron configuration

What does the notation oxygen-16 mean?

• It means the oxygen atom has 16 protons.

• It means the oxygen atom has 16 neutrons.

• It means the oxygen atom has a mass number of 16.

• It means the oxygen atom has 16 electrons.

Why do different isotopes of the same element react in the same way?

• Because they have the same number of protons and electrons

• Because they have different numbers of neutrons

• Because they have different atomic masses

• Because they are in different states of matter

What is the standard isotope that all atomic masses are based on?

• Carbon-12

• Oxygen-16

• Hydrogen-1

• Nitrogen-14

Relative isotopic mass is:

• The mass of an isotope relative to 1/12th of the mass of carbon-12

• The mass of an isotope relative to the mass of hydrogen

• The mass of an isotope relative to the mass of oxygen-16

• The mass of an isotope relative to the mass of nitrogen-14

What is relative atomic mass?

• The mass of an atom relative to carbon-12

• The number of protons in an atom

• The number of neutrons in an atom

• The total number of protons and neutrons in an atom

What does the weighted mean mass mean?

• It is the average mass of a set of items, each weighted by its importance.

• It is the total mass of all items divided by the number of items.

• It is the mass of the heaviest item in a set.

• It is the mass of the lightest item in a set.