ATOMS TESTS

What is the smallest non-living particle that all matter is made of?

• Molecule

• Atom

• Cell

• Compound

Answer explanation

The smallest non-living particle that makes up all matter is the atom. Atoms combine to form molecules and compounds, but they are the fundamental building blocks of matter.

Tags

NGSS.MS-PS1-1

What is the charge of a proton?

• Neutral

• Negative

• Positive

• Variable

Answer explanation

A proton carries a positive charge, which is fundamental to its identity as a subatomic particle. This distinguishes it from electrons, which have a negative charge, and neutrons, which are neutral.

What is the charge of a neutron?

• Positive

• Negative

• Neutral

• Variable

Answer explanation

A neutron has no electric charge, making it neutral. This distinguishes it from protons, which are positively charged, and electrons, which are negatively charged.

What is the charge of an electron?

• Positive

• Negative

• Neutral

• Variable

Answer explanation

The charge of an electron is negative, which is fundamental to its role in electricity and chemistry. Electrons carry this negative charge, contrasting with protons, which have a positive charge.

Tags

NGSS.MS-PS2-3

What happens when the number of protons in an atom changes?

• It becomes an isotope

• It changes into a different element

• It becomes an ion

• It remains the same

Answer explanation

When the number of protons in an atom changes, it alters the atomic number, which defines the element. Therefore, the atom becomes a different element, making 'It changes into a different element' the correct choice.

Tags

NGSS.HS-PS1-8

Match the following atomic changes with their outcomes.

• Change in neutron count

• It becomes an isotope

• Change in proton count

• It becomes an ion

• No change in subatomic particles

• It changes into a different element

• Change in electron count

• It remains the same

When electrons are removed from an atom, it becomes (a)  

• It becomes a cation

• It becomes an anion

• It becomes neutral

• It remains the same

Answer explanation

When electrons are removed from an atom, it loses negative charge, resulting in a net positive charge. This positively charged atom is called a cation.

What happens when electrons are added to an atom?

• It becomes a cation

• It becomes an anion

• It becomes neutral

• It remains the same

Answer explanation

When electrons are added to an atom, it gains a negative charge, resulting in the formation of an anion. This occurs because the number of negatively charged electrons exceeds the number of positively charged protons.

The atomic number of an element is the (a)   .

• Number of electrons

• Number of protons

• Number of neutrons

• Number of atoms

Answer explanation

The atomic number of an element is defined as the number of protons in its nucleus. This number determines the element's identity and its position in the periodic table, making 'Number of protons' the correct choice.

What is the atomic mass of an element?

• Number of protons

• Number of electrons

• Number of protons and neutrons

• Number of neutrons

Answer explanation

The atomic mass of an element is determined by the total number of protons and neutrons in its nucleus. Protons and neutrons contribute to the mass, while electrons have negligible mass, making 'Number of protons and neutrons' the correct choice.