Periodic Table

Question 1

General characteristics of Groups
(Vertical Column of elements -top to bottom-)

Answer 1

1. Elements in the same group have the same number of valence electrons. (specify how many)
2. Elements in the same group exhibit similar chemical reactions.
3. Forms similar chemical formulas

Question 2

General characteristics of elements in periods
(Horizontal row, Left to Right)

Answer 2

1. Elements in the same period have atoms with the same number of electrons shells (specify how many)
2. The number of electron shells is shown in the eletronic configuration (no. Of sets)

Question 3

Metals;

Answer 3

+ charge
Tendency to lose valence electrons
Basic oxides

Question 4

Non metals;

Answer 4

• charge
  Tendency to gain valence electrons
  Acidic oxide

Question 5

General trend down groups

Answer 5

1. number of electron shell increases down the group
2. Group 14,15,16 changes from non-metals (top) to metals (bottom) -metallic properties increases

Question 6

General trend across periods

Answer 6

1. Number of valence electrons increases by 1 for each consecutive element across the period.
2. Properties change from; metals -> metalloids -> non metal
   Metallic properties decreases across the period. ( I.e. tendency to lose valence electrons decreases across the period.

Question 7

Physical properties of group 1 Alkali metals

Answer 7

-shiny silver grey appearance
-soft metals (can be easily compressed - malleable/ cut by a knife)
-low melting points (compared to other metals)
-Low density (Linak)
-good conductors of heat & electricity

Question 8

Chemical properties of group 1 alkali metals

Answer 8

Known as the reactive metals.
-reacts rapidly/readily/vigorously with water to form alkali & hydrogen gas (exothermic reactions)
-reacts vigorously with group 17
-high tendency to lose its 1 valence electron to form a positive ion

Question 9

How are group 1 alkali metals stored?

Answer 9

Stored in mineral oil as they oxidise readily in air to form a layer of oxide on its surface.

Question 10

Physical properties of group 17 halogens

Answer 10

-coloured substances
-low melting & boiling point (non-metals)
-poor conductors of heat & electricity (non-metals)
-brittle (I.e. iodine crystals)

Question 11

Chemical properties of groups 17 halogens

Answer 11

Known as the non-reactive metals
-combines with hydrogen to form acidic substances (I.e. H2 + CL2 -> 2HCL)
-combines with metals to form salts ( Halogen -> salt former )
-reacts vigorously with group 1 metals
-High tendency to gain an electron to form a negative ion
-exists as diatomic atoms at room temperature

Question 12

Properties of group 18 noble gases

Answer 12

-chemically unreactive gases
-atoms in group 18 do not form compounds with other elements as they have a completely filled valence shell.
Hence, these elements do not gain, lose or share electrons with atoms of other elements.
-exists as a monoatomic atom at room temperature

Question 13

Trends down group 1

Answer 13

-elements get softer (more malleable) down the group (hardness decreases)
-density increases (with exception of potassium)
-melting & boiling point decreases
-atomic radius increases
-reactivity increases

Question 14

Observation of 2Li + 2H2O

Answer 14

2LiOH+H2
Reacts readily with water
Fizzes & floats on the surface of water
Effervescence observed

Question 15

Observation of 2Na + 2H2O

Answer 15

2NaOH + H2
Reacts vigorously with water
Fizzes rapidly on the surface of water as it melts to form a white ball. May explode with an orange flame.

Question 16

Observation of 2K + 2H2O

Answer 16

2KOH + H2
Reacts explosively with water
Explode when in contact with water; fizzes as it explodes and burns with a Lilac flame

Question 17

Trends down group 17

Answer 17

-Density increases
-Melting & Boiling point increases
-colour intensity of element increases
-Reactivity decreases

Question 18

Displacement reactions & observations

Answer 18

-Principle of displacement: more reactive element displacing less reactive element from its compound.
-Displacement reactions are redox reactions
-Concept: more reactive halogen will displace the less reactive halide from its salt solution.

Question 19

Colour of Florine when dissolved in water

Answer 19

Colourless

Question 20

Colour of Chlorine dissolved in water

Answer 20

Pale yellow

Question 21

Colour of bromine dissolved in water

Answer 21

Orange

Question 22

Colour of Iodine dissolved in water

Answer 22

Brown

Question 23

Describe what happens when chlorine displaces bromine

Answer 23

Chlorine is more reactive than bromine, chlorine will displace bromide ions from its salt solution

Question 24

State and explain what you would observe when a jet of chlorine gas is aimed filter paper soaked in solution of potassium iodide

Answer 24

Colourless filter paper turns brown.
Chlorine is more reactive than iodine. Chlorine will displace iodine from potassium iodide

Question 25

State the electronic structures of lithium & sodium and explain why they are in the same group of periodic table

Answer 25

Sodium is 2,8,1
Lithium is 2,1
They have same number of 1 valence electrons

Question 26

Sodium placed into beaker with water & potassium in another.
Describe 2 similarities & 1 difference in observation

Answer 26

Similarities:
-effervescence observed, colour flame observed
Difference:
-Potassium shows a more vigorous reaction with water compared to sodium