Atomic Strucure And Periodic Table

Question 1

What are the three subatomic particles in an atom?

Answer 1

Protons, neutrons, and electrons.

Question 2

What is the charge of a proton?

Answer 2

+1 (positive).

Question 3

What is the charge of a neutron?

Answer 3

0 (neutral).

Question 4

What is the charge of an electron?

Answer 4

-1 (negative)

Question 5

Where are protons and neutrons found in an atom?

Answer 5

In the nucleus.

Question 6

Where are electrons found in an atom?

Answer 6

In energy levels (shells) around the nucleus.

Question 7

What is the atomic number of an element?

Answer 7

The number of protons in an atom.

Question 8

What is the mass number of an atom?

Answer 8

The total number of protons and neutrons in an atom.

Question 9

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

Answer 9

Mass number - Atomic number.

Question 10

What are isotopes?

Answer 10

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 11

What determines the chemical properties of an element?

Answer 11

The number of electrons in the outer shell.

Question 12

Why are noble gases (Group 0) unreactive?

Answer 12

They have a full outer electron shell.

Question 13

Who first proposed the idea of atoms?

Answer 13

John Dalton in the early 19th century.

Question 14

What did J.J. Thomson discover?

Answer 14

The electron, leading to the “plum pudding model” of the atom.

Question 15

What experiment did Rutherford and Marsden conduct?

Answer 15

The gold foil experiment.

Question 16

What did Rutherford’s experiment show about the atom?

Answer 16

It has a small, dense, positively charged nucleus, with electrons orbiting around it.

Question 17

How did Bohr improve Rutherford’s model?

Answer 17

He proposed that electrons orbit the nucleus in fixed energy levels (shells).

Question 18

What did James Chadwick discover?

Answer 18

The neutron, explaining the missing mass in atoms

Question 19

How are electrons arranged in an atom?

Answer 19

In energy levels (shells).

Question 20

What is the maximum number of electrons in the first shell?

Answer 20

2 electrons

Question 21

What is the maximum number of electrons in the second and third shells?

Answer 21

8 electrons each.

Question 22

How do you determine an element’s group number from its electronic structure?

Answer 22

The number of electrons in the outer shell.

Question 23

How do you determine an element’s period number from its electronic structure?

Answer 23

The number of electron shells.

Question 24

What is the electronic structure of sodium (atomic number 11)?

Answer 24

2, 8, 1.

Question 25

Why do elements in the same group have similar chemical properties?

Answer 25

They have the same number of electrons in their outer shell.

Question 26

Who developed the modern periodic table?

Answer 26

Dmitri Mendeleev in 1869

Question 27

How did Mendeleev arrange the elements in the periodic table?

Answer 27

By atomic mass, but he also grouped elements with similar properties together.

Question 28

Why did Mendeleev leave gaps in his periodic table?

Answer 28

For undiscovered elements that he predicted based on patterns.

Question 29

How is the modern periodic table arranged?

Answer 29

By atomic number (number of protons).

Question 30

What are groups in the periodic table?

Answer 30

Vertical columns containing elements with similar chemical properties.

Question 31

What are periods in the periodic table?

Answer 31

Horizontal rows that show the number of electron shells.

Question 32

What are the main types of elements in the periodic table?

Answer 32

Metals (left side) and non-metals (right side).

Question 33

What is a metalloid (semi-metal)?

Answer 33

An element that has properties of both metals and non-metals (e.g., silicon).

Question 34

What are the properties of alkali metals?

Answer 34

Soft, low-density, highly reactive, and have low melting points.

Question 35

How does reactivity change as you go down Group 1?

Answer 35

Reactivity increases because the outer electron is further from the nucleus and is more easily lost.

Question 36

What happens when alkali metals react with water?

Answer 36

They form a metal hydroxide and hydrogen gas.

Question 37

What is the word equation for sodium reacting with water?

Answer 37

Sodium + Water → Sodium Hydroxide + Hydrogen.

Question 38

Why are alkali metals stored in oil?

Answer 38

To prevent them from reacting with oxygen and moisture in the air

Question 39

What are the properties of halogens?

Answer 39

Non-metals, diatomic molecules, and highly reactive.

Question 40

How does reactivity change as you go down Group 7?

Answer 40

Reactivity decreases because the outer shell is further from the nucleus, making it harder to gain an electron.

Question 41

What is the trend in boiling points of the halogens?

Answer 41

Boiling points increase as you go down the group.

Question 42

What is a displacement reaction?

Answer 42

A more reactive halogen can displace a less reactive halogen from its compound

Question 43

Give an example of a halogen displacement reaction.

Answer 43

Chlorine + Potassium Bromide → Potassium Chloride + Bromine.

Question 44

What are the properties of noble gases?

Answer 44

They are unreactive, colorless gases with low boiling points.

Question 45

Why are noble gases unreactive?

Answer 45

They have a full outer electron shell

Question 46

How does boiling point change as you go down Group 0?

Answer 46

Boiling points increase due to stronger intermolecular forces.