Atoms

Question 1

What are atoms?

Answer 1

Atoms are the tiny building blocks of all substances.

Question 2

How small is an atom compared to everyday objects?

Answer 2

A 50p piece contains about 77,400,000,000,000,000,000 atoms.

Question 3

What do atoms contain?

Answer 3

Atoms contain protons, neutrons, and electrons.

Question 4

Where is the nucleus located in an atom?

Answer 4

The nucleus is located in the middle of the atom.

Question 5

What does the nucleus contain?

Answer 5

The nucleus contains protons and neutrons.

Question 6

What is the radius of the nucleus?

Answer 6

The nucleus has a radius of about 1 x 10-14 m (around 1/10,000 of the radius of an atom).

Question 7

What charge does the nucleus have?

Answer 7

The nucleus has a positive charge because of the protons.

Question 8

Where is most of the atom’s mass concentrated?

Answer 8

Almost the whole mass of the atom is concentrated in the nucleus.

Question 9

Where are electrons located?

Answer 9

Electrons move around the nucleus in electron shells.

Question 10

What charge do electrons have?

Answer 10

Electrons are negatively charged.

Question 11

How does the size of electrons compare to protons and neutrons?

Answer 11

Electrons are tiny and have virtually no mass.

Question 12

What determines the size of the atom?

Answer 12

The volume of the electrons’ orbits determines the size of the atom.

Question 13

What is the relative mass and charge of a proton?

Answer 13

Relative mass = 1, Charge = +1

Question 14

What is the relative mass and charge of a neutron?

Answer 14

Relative mass = 1, Charge = 0

Question 15

What is the relative mass and charge of an electron?

Answer 15

Relative mass = Very small (often taken as zero), Charge = -1

Question 16

Why are atoms neutral?

Answer 16

Atoms are neutral because they have an equal number of protons and electrons.

Question 17

What happens to an atom’s charge if it gains or loses electrons?

Answer 17

If the number of protons doesn’t equal the number of electrons, the atom has an overall charge and becomes an ion.

Question 18

What does it mean if an atom has a 2- charge?

Answer 18

It means the atom has gained two extra electrons.

Question 19

What does the atomic number tell us?

Answer 19

The atomic number tells us the number of protons and electrons in an atom. (Which are always the same in an atom).

Question 20

What does the mass number tell us?

Answer 20

The mass number tells us the total number of protons and neutrons in an atom.

Question 21

How do you find the number of neutrons in an atom?

Answer 21

Subtract the atomic number from the mass number to get the number of neutrons.

Question 22

What is a nuclear symbol?

Answer 22

A nuclear symbol represents an atom with its atomic (proton and electron) number and mass number (protons and neutrons).

Question 23

Q1: An atom of gallium has an atomic number of 31 and a mass number of 70. How many protons, neutrons, and electrons does it have?

Answer 23

Protons = 31, Neutrons = 39 (70 - 31), Electrons = 31 (assuming it’s neutral).