Topic 2 - Atomic Structure

Subatomic particles with a negative charge

• Electrons

• Neutrons

• Protons

• Quarks

Answer explanation

Electrons are subatomic particles with a negative charge. They are the correct choice because they are the only particles mentioned that have a negative charge.

Subatomic particles with a positive charge

• neutrons

• atomic mass

• protons

• isotopes

Answer explanation

Protons are subatomic particles with a positive charge. They are found in the nucleus of an atom and determine the element's atomic number.

Subatomic particles that are neutral in charge

• Neutrons

• Protons

• Nucleus 

• Electrons

Answer explanation

Neutrons are subatomic particles that are neutral in charge.

A helium nucleus with two protons and two neutrons is called a(n) ____.  

• alpha particle

• electroscope

• beta particle

• gamma ray

Answer explanation

A helium nucleus with two protons and two neutrons is called an alpha particle. It is the correct choice.

Most of the mass in an atom is made up of _____________________?

• protons and electrons

• protons and neutrons

• neutrons and electrons

• electrons and quarks

Answer explanation

The majority of an atom's mass is composed of protons and neutrons, which are found in the nucleus.

The number 16 for the atomic element sulfur is the

• ionic number

• isotope

• atomic mass

• atomic number

Answer explanation

The atomic number of an element represents the number of protons in its nucleus. For sulfur, the atomic number is 16, indicating it has 16 protons. This distinguishes sulfur from other elements and is a fundamental property of its atomic structure.

How many electrons does potassium K contain? (click to see image)

• 19

• 39

• 20

• 40

Answer explanation

Potassium (K) contains 19 electrons, which is the correct choice.

How many protons are in an atom with an atomic number of 20, an atomic mass of 45, and a charge of +2?

• 20

• 10

• 2

• 18

Answer explanation

The atomic number of an atom represents the number of protons. In this case, the atom has an atomic number of 20, so it has 20 protons. The atomic mass and charge are not relevant to determining the number of protons.

How many electrons are in an atom that has an atomic number of 34, an atomic mass of 74 and a charge of -2?

• 34

• 36

• 2

• 40

Answer explanation

The atomic number represents the number of protons in an atom. Since the atom has a charge of -2, it means it has gained 2 electrons. Therefore, the total number of electrons in the atom is 34 + 2 = 36. The correct answer is 36.

1.  What is the shape of an s orbital?

• sphere

• dumbbell

• double dumbbell

• TOO COMPLEX TO KNOW IT.

Answer explanation

The shape of an s orbital is a sphere.