1.3 The periodic table

Question 1

How are the elements listed and approximately how many are there?

Answer 1

They are listed in the periodic table and there are approximately 100

Question 2

Elements can be classified into two groups based on their properties; what are these groups?

Answer 2

Metals and non-metals

Question 3

Compare the properties of
metals and non-metals

Answer 3

Metals:

High melting/boiling point, high heat/electrical conductivity, high density, shiny, malleable, form basic oxides

Non-metals:

Low melting/boiling point, low heat/electrical conductivity, low density, dull, brittle, form acidic oxides

Question 4

What is formed when a metal reacts with a
non-metal?

Answer 4

An ionic compound (made of positive and negative ions).

Question 5

What is formed when a non-metal reacts with a
non-metal?

Answer 5

A molecular compound containing covalently bonded atoms.

Atoms share electrons, as opposed to transferring electrons between
each other (ionic compounds).

Question 6

What are the columns of the periodic table called?

Answer 6

Groups

Question 7

What are the rows of the periodic table called?

Answer 7

Periods

Question 8

Are elements in the same group similar or different?

Answer 8

They may have similar chemical properties, as they have the same
number of outer shell electrons.

Question 9

In terms of energy levels, what are
the differences between elements
of the same period?

Answer 9

They have the same number of energy levels

Question 10

Electrons occupy particular energy
levels, with each electron in an atom at a particular energy level; which available energy level do electrons occupy?

Answer 10

The lowest available energy level

Question 11

What are the elements of Group 0 known as?

Answer 11

The noble gases

Question 12

What makes the periodic table periodic?

Answer 12

Similar properties of elements occur at regular intervals

Question 13

Elements in the same group have the same number of electrons in their outer shell; what does this tell us about their
chemical properties?

Answer 13

They have similar chemical properties

Question 14

In terms of shells, what is the
difference between elements
in the same period?

Answer 14

They have the same number of shells

Question 15

What change in shell number is seen as you move down a group?

Answer 15

The number of shells increases

Question 16

How were early periodic tables ordered?

Answer 16

By the order of their atomic masses

Question 17

What discovery explained why the order of atomic masses was not always correct?

Answer 17

Isotopes

Question 18

How did Mendeleev overcome problems when creating the periodic table?

Answer 18

By leaving gaps for undiscovered elements

Question 19

How did Mendeleev order the elements of the periodic table?

Answer 19

By atomic mass and similar properties

Question 20

What are the majority of elements?

Answer 20

Metals

Question 21

What elements react to form positive ions?

Answer 21

Metals

Question 22

What elements do not react to form positive ions?

Answer 22

Non-metals

Question 23

What are elements in Group 1 known as?

Answer 23

The alkali metals

Question 24

State three characteristics of
the alkali metals

Answer 24

-All have one
electron in their
outer shell

-Low density

-Stored in oil (to
prevent reactions
with oxygen or
water)

-Soft (can be cut
with a knife)

Question 25

How do Group 1 elements react with non-metals? Why are these reactions similar for the different Group 1 elements?

Answer 25

They form ionic compounds that are soluble white solids and form colourless solutions They all have one electron in their outer shell.

Question 26

How do Group 1 elements react with water?

Answer 26

They release hydrogen and form hydroxides which dissolve to form alkaline solutions. They react vigorously with water, fizzing and moving around on the surface.

Question 27

How does the reactivity change moving down Group 1? Why?

Answer 27

Reactivity increases as the atoms get larger and the distance between the nucleus and the outer electrons increases and thus attraction from the nucleus decreases, allowing them to more easily lose electrons.

Question 28

State five characteristics of Group 7

Answer 28

-7 electrons in outer shell -Coloured vapours -Diatomic molecules -Form ionic salts with metals -Form molecular compounds with non-metals

Question 29

State the Group 7 elements and their states of matter.

Answer 29

-Fluorine (F), F2 is a pale yellow gas. -Chlorine (Cl), Cl2 is a pale green gas. -Bromine (Br) Br2 is dark brown liquid -Iodine (I), I2 is a grey solid.

Question 30

State three changes that occur in Group 7 as you move down the group

Answer 30

-Higher relative molecular mass -Higher melting and boiling point -Less reactive – less easily gain electrons

Question 31

A more reactive halogen displaces a less reactive one from an aqueous solution of its salt; explain the trend in reactivity of halogens in these reactions

Answer 31

Reactivity decreases down the group. As we go down the group, the atoms get larger, so an incoming electron will be less tightly held by the attractive forces from the nucleus. That’s why Cl2 displaces Br– and I–

Question 32

Describe the properties of noble gases. Discuss the trend in boiling point down the group.

Answer 32

Non-metals, gases, low boiling points, unreactive (full outer shell; they don’t easily accept or lose electrons). The boiling point increases down the group, as the atoms get heavier.

Question 33

State the colours of flames observed when lithium, sodium, and potassium burn in oxygen

Answer 33

Crimson-red, Li Yellow-orange, Na Lilac, K

Question 34

Compare the Group 1 metals and transition metals. (Triple)

Answer 34

The group 1 metals and transition metals are heat and electricity conductors. They are shiny when polished and form ionic compounds with non metals. The transition metals have higher densities and higher melting points than Group 1 metals. They are less reactive and harder than Group 1 metals.

Question 35

State three common characteristics of transition metals. (Triple)

Answer 35

-Ions with different charges -Coloured compounds -Catalytic properties

Question 36

What is a catalyst?

Answer 36

A catalyst is a chemical substance that increases the rate of a chemical reaction. It is not used up over the course of the reaction.

Question 37

State the colours of flames observed when lithium, sodium, and potassium burn in oxygen

Answer 37

Crimson-red, Li Yellow-orange, Na Lilac, K