Atomic structure and the periodic table

Question 1

What is the name of the smallest part of an element that makes up all substances?

Answer 1

An atom

Question 2

How can a compound be separated?

Answer 2

By a chemical reaction

Question 3

What do all chemical symbols, e.g. Na and O, have to start with?

Answer 3

A capital letter

Question 4

What is a mixture?

Answer 4

Two or more elements, or compounds, that are not chemically bonded together.

Question 5

Approximately how many different elements are there?

Answer 5

There are 118 different elements.

Question 6

How would you separate a salt from water?

Answer 6

Crystallisation

Question 7

What is a compound?

Answer 7

Two or more different elements that are chemically combined.

Question 8

How would you separate a solid from a liquid?

Answer 8

Filtration

Question 9

How would you separate two soluble liquids?

Answer 9

Distillation

Question 10

Why might a scientist decide to change or replace an existing model?

Answer 10

New experimental evidence is put forward.

Question 11

The discovery of what sub-atomic particle led to the plum pudding model of the atom?

Answer 11

The electron

Question 12

Describe how you could use chromatography to identify a banned food dye in food colouring.

Answer 12

• Place food dyes on pencil line on chromatography paper. - Place paper in solvent (e.g. water) - The dye will dissolve in the water and spread up the paper. - The colours in the dye will separate. - Compare the patterns of the food dyes with the chromatogram of the banned food dye.

Question 13

What two conclusions about the atom were drawn from the results of the alpha particle scattering experiment?

Answer 13

• The mass was concentrated at the centre (the nucleus) - The nucleus was charged.

Question 14

What are the relative charges of protons, electrons and neutrons?

Answer 14

• Protons +1 - Electrons -1 - Neutrons 0

Question 15

Who adapted the nuclear model of the atom by suggesting that electrons orbit at specific distances?

Answer 15

Niels Bohr

Question 16

What are the relative masses of protons, electrons and neutrons?

Answer 16

• Proton 1 - Electron very small (1/2000) - Neutron 1

Question 17

What are the names of the sub-atomic particles in the nucleus of the atom?

Answer 17

Protons and Neutrons

Question 18

What is the charge on an atom?

Answer 18

There is no overall charge on an atom

Question 19

What relationship is there between the number of protons and electrons in an atom?

Answer 19

The number of protons equals the number of electrons.

Question 20

Who discovered the neutron about 20 years after the discovery of the nucleus?

Answer 20

James Chadwick

Question 21

What is the approximate size of the radius of an atom?

Answer 21

0.1 nm (1 x 10-10 m)

Question 22

Approximately how many times smaller is the radius of the nucleus of the atom?

Answer 22

The radius of a nucleus is less than 1/10000 of that of the atom (i.e. over 10000 times smaller).

Question 23

What is the definition of an isotope?

Answer 23

Atoms of the same element with a different number of neutrons

Question 24

How do you calculate the mass number of an atom?

Answer 24

Mass number is the sum of protons and neutrons.

Question 25

What does the atomic number tell you about the particles in an atom?

Answer 25

Atomic number tells you the number of protons in an atom.

Question 26

Why is the table of elements called a ‘Periodic Table’?

Answer 26

Because elements with similar properties occur at regular intervals.

Question 27

What are the columns in the Periodic Table called?

Answer 27

Groups

Question 28

What are the rows in the Periodic Table called?

Answer 28

Periods

Question 29

How are the elements in the Periodic Table arranged?

Answer 29

Atomic (proton) number

Question 30

Calculate the relative atomic mass of chlorine given the percentage abundances of the following isotopes of Chlorine: 75 % Chlorine-35 and 25% Chlorine-37

Answer 30

(75% x 35) + (25% x 37) = 35.5

Question 31

What similarities are there between elements in the same group?

Answer 31

- Same number of electrons in outer energy level/shell - Similar Properties

Question 32

What does the Group Number tell you about the electrons in an element?

Answer 32

Group Number = Number of electrons in outer energy level / shell.

Question 33

What charge do non-metal ions (except Hydrogen) have?

Answer 33

Negative

Question 34

How were elements in the early periodic tables arranged?

Answer 34

By atomic weights

Question 35

Where are metals found on the Periodic Table?

Answer 35

Metals are on the Left-Hand Side of the Periodic Table

Question 36

Where are the non-metals on the Periodic Table?

Answer 36

Non-metals are on the Right-Hand Side of the Periodic Table

Question 37

Who designed a Periodic Table that left gaps for undiscovered elements?

Answer 37

Mendeleev

Question 38

What are the elements in Group 0 called?

Answer 38

Noble gases

Question 39

What charge do metal ions have?

Answer 39

Positive

Question 40

In terms of electron arrangement, explain why noble gases are unreactive.

Answer 40

They have a full outer shell of electrons. (Helium has 2 electrons in outer shell, all other noble gases have 8 electrons in outer shell).

Question 41

How does the boiling point of noble gases change as you go down the group?

Answer 41

It increases

Question 42

What are the elements in Group 7 of the Periodic Table called?

Answer 42

Halogens

Question 43

What is the name given to the elements in Group 1 of the Periodic Table?

Answer 43

Alkali Metals

Question 44

Which group of elements form molecules made up of pairs of atoms (diatomic)?

Answer 44

The Halogens (Group 7)

Question 45

Name the products produced when sodium reacts with Chlorine?

Answer 45

Sodium chloride

Question 46

Name the products produced when sodium reacts with Oxygen?

Answer 46

Sodium oxide

Question 47

Name the products produced when sodium reacts with Water

Answer 47

Sodium hydroxide + hydrogen

Question 48

What happens to the melting and boiling points of Halogens as you go down the group?

Answer 48

Melting and boiling points increase

Question 49

What happens to the reactivity of the Halogens as you go down the group?

Answer 49

Reactivity decreases

Question 50

What happens the the reactivity of alkali metals as you go down the group?

Answer 50

Reactivity Increases

Question 51

Name the type of reaction shown by the word equation below. chlorine + sodium bromide → sodium chloride + bromine

Answer 51

Displacement Reaction

Question 52

What does this reaction tell you about the reactivity of chlorine and bromine?

Answer 52

Chlorine is more reactive than bromine (or vice versa)