C1: Atomic Structure and The Periodic Table

Question 1

How are elements on the periodic table ordered?

Answer 1

By atomic number.

Question 2

What is a mixture?

Answer 2

2+ elements mixed together but not chemically bonded.

Question 3

Describe the plum pudding model of the atom.

Answer 3

A solid ball of positive charge with negatively charged electrons embedded in it.

Question 4

Describe the difference between the plum pudding model and the nuclear model of the atom. [4 marks]

Answer 4

In the plum pudding model, there is a positively charged, solid sphere with negatively charged electrons embedded within it. There is no empty space. However, in the nuclear model, there is a central positive nucleus, with mostly empty space and negative electrons in shells orbiting around the nucleus.

The mass in the plum pudding model is distributed equally throughout the sphere, whereas the mass in the nuclear model is concentrated in the nucleus.

Question 5

Describe how the new evidence from the alpha particle scattering experiment led to a change in the atomic model. [6 marks]

Answer 5

Most alpha particles went straight through the atom, proving that it was mostly empty space.

Some alpha particles were redirected slightly, showing that the nucleus is positively charged, and had repelled the positive alpha particles.

A few alpha particles were deflected in the opposite direction, proving that the atom’s mass was concentrated centrally in a small nucleus, which the alpha particles had collided with.

Question 6

Which scientist suggested that electrons orbit the nucleus at specific distances?

Answer 6

Niels Bohr.

Question 7

Which scientist discovered neutrons?

Answer 7

James Chadwick.

Question 8

Why do atoms have no overall charge?

Answer 8

Because they have the same number of protons and neutrons, so their positive and negative charges cancel each other out.

Question 9

What does the atomic number represent?

Answer 9

The number of protons and electrons.

Question 10

What does the mass number represent?

Answer 10

The number of protons plus neutrons.

Question 11

What is the charge and mass of a proton?

Answer 11

+1 charge and 1.

Question 12

What is the charge and mass of a neutron?

Answer 12

0 charge and 1.

Question 13

What is the charge and mass of an electron?

Answer 13

-1 charge and very small.

Question 14

Where is most of the mass in an atom concentrated?

Answer 14

The nucleus.

Question 15

What is an isotope?

Answer 15

A version of an atom with the same number of protons and electrons but a different number of neutrons.

Question 16

How do you calculate the relative atomic mass of an element given the percentage abundance of its isotopes?

Answer 16

Multiply each atomic mass by its abundance, add all the values together and divide the total value by 100 percent.

Question 17

How many electrons can be arranged in each of the shells? (Electronic structure).

Answer 17

2,8,8

Question 18

What does group number represent in the periodic table?

Answer 18

The number of electrons in the outer shell.

Question 19

What was the original periodic table ordered by?

Answer 19

Atomic weight.

Question 20

What did Mendeleev do to improve the periodic table?

Answer 20

He left gaps for undiscovered elements and in some places changed the order based on atomic weights.

Question 21

Why was Mendeleev’s contribution credible?

Answer 21

Elements with properties predicted by Mendeleev were discovered and filled the gaps. Knowledge of isotopes made it possible to explain why the order based on atomic weights was not always correct.

Question 22

What charge do metal ions have?

Answer 22

Positive.

Question 23

What charge do non-metal ions have?

Answer 23

Negative.

Question 24

Where are metals found on the periodic table?

Answer 24

The left side.

Question 25

What are the properties of group 0 elements?

Answer 25

NOBLE GASES are unreactive and don’t form molecules easily because they have full outer shells.

Question 26

What happens to the boiling point of group 0 noble gases as you go down the group?

Answer 26

Boiling point increases going down the group.

Question 27

What is the name of group 0?

Answer 27

Noble gases.

Question 28

What is the name of group 1?

Answer 28

Alkali metals.

Question 29

What happens going down the group 1 alkali metals?

Answer 29

Reactivity increases going down the group.

Question 30

What is the name of group 7?

Answer 30

Halogens.

Question 31

What happens going down the group 7 halogens?

Answer 31

The reactivity decreases going down the group.

Question 32

Why are the transition metals different from group 1 alkali metals?

Answer 32

Transition metals are much stronger, denser and harder than the group 1 elements.

Question 33

What charges do transition metal ions have?

Answer 33

Different charges.

Question 34

How are transition metals useful?

Answer 34

They are used as catalysts.

Question 35

Where are transition metals on the periodic table?

Answer 35

The middle.