Elements Answers

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If we have a sample of silicon (Si) atoms that has 14 protons, 14 electrons, and 18 neutrons

A
silicon-14
B
silicon-32
C
silicon-46
D
silicon-153
2
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A potassium atom (atomic number 19) loses an electron while forming a bond with another atom.

A
It is a negative ion that has one less valence electron than a neutral potassium atom.
B
It is a negative ion that has one more valence electron than a neutral potassium atom.
C
It is a positive ion that has one less valence electron than a neutral potassium atom.
D
It is a positive ion that has one more valence electron than a neutral potassium atom.
3

The model below shows a carbide ion.

Question illustration
A
remove 2 electrons
B
add 2 electrons
C
remove 4 electrons
D
add 4 electrons
4

Uranium is an element that is often used in nuclear power plants. Uranium atoms are very large, and the substance can be dangerous if it is not carefully contained.

A
They each have the same number of nuclear particles.
B
They each have the same number of neutral particles.
C
They each have the same number of neutrons.
D
They each have the same number of protons.
5

What can be added to an atom to cause a nonvalence electron in the atom to temporarily become a valence electron?

A
energy
B
mass
C
neutrons
D
electrons
6

The simple model below is a neutral magnesium (Mg) atom with the element’s most common mass number.

Question illustration
A
It must lose two neutrons and become a different isotope.
B
It must gain two neutrons and become a different isotope.
C
It must lose two electrons and become an ion.
D
It must gain two electrons and become an ion.
7

The chemical symbol for the element calcium is Ca. What would be the symbol representing calcium atoms that have lost two electrons?

A
Ca–
B
Ca+
C
Ca–2
D
Ca+2
8

One way in which elements differ from each other is the structure of the electron cloud in each element’s atoms. In an electron cloud, an electron that is farther away from the nucleus has

A
a greater charge than an electron near the nucleus.
B
a smaller charge than an electron near the nucleus
C
a higher energy than an electron near the nucleus.
D
a lower energy than an electron near the nucleus.
9

Which describes an atom that has fewer neutrons than protons and more electrons than protons?

A
negative compound
B
positive compound
C
positive ion
D
negative ion
10

All large radioactive atoms decay into smaller atoms by releasing alpha particles. Each alpha particle has 2 protons, 2 neutrons, and 0 electrons. The table below describes several neutral, low-mass atoms.

Question illustration
A
lithium-7
B
helium-4
C
hydrogen-2
D
helium-2

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