IPC 1.1 Atomic Structure Test Review

List the phases of water in order, from the phase with the slowest molecular movement to the phase with the fastest

molecular movement.

• Gas - Liquid - Solid

• Liquid - Solid - Gas

• Solid - Liquid - Gas

Chlorine’s (Cl) relative atomic mass is 35.5. This half number is due to

• isotopes

• a half proton

• a half neutron

• a half electron

The atomic mass of an element is defined as the weighted average mass of that element’s

• radioactive isotopes

• naturally occurring isotopes

• most abundant isotope

• least abundant isotope

What is the total number of electrons in an Mg²⁺ ion?

• 10

• 24

• 2

• 12

Atoms of ¹⁶O, ¹⁷O, and ¹⁸O have the same number of

• protons, but a different number of electrons

• protons, but a different number of neutrons

• neutrons, but a different number of protons

• electrons, but a different number of protons

A Ca²⁺ ion differs from a Ca⁰ atom in that the Ca²⁺ ion has

• more electrons

• fewer electrons

• fewer protons

• more protons

Which statement about an element’s average atomic mass is correct?

• It is determined by counting the number of isotopes in a sample of the element.

• It is a weighted average, so common isotopes have a greater effect than uncommon ones.

• It is based on an isotope’s charge, so negatively charged isotopes have a greater effect than positive ones.

• It is equal to one-twelfth the mass of the most common isotope.

Which of the following is an atom that has gained an electron

• negative ion

• positive ion

• isotope

• stable atom

An atom’s mass number if 210 and its atomic number is 85. How many neutrons does the atom have?

• 85

• 125

• 210

• 295

The atomic number of this element is 14. How many electrons does it have?

• 14

• 32

• 46

• 18