Periodic Table

Question 1

What changes when moving top to bottom down the periodic table?

Answer 1

• Proton number increases not consecutively
• Number of electron shells increases consecutively

Question 1

What changes when we move left to right across the periodic table?

Answer 1

• Proton Number increases consecutively
• Number of valence electrons increases consecutively
• Different chemical properties
• Elements change from metals to non-metals

Question 2

How does reactivity change when going down group 1 (alkali metals)

Answer 2

Reactivity increases

Question 3

State physical properties of alkali metals.

Answer 3

• Lower melting points and boiling points compared to other metals
• Lower density compared to other metals
• Soft (Able to cut easily)
• Shiny silvery solids
• Conducts Electricity

Question 4

State the chemical properties of alkali metals.

Answer 4

• Strong alkalis
• turns colour of universal indicator green to violet

Question 5

State the observations made when sodium reacts with water.

Answer 5

• Sodium dart around the surface of water (less dense than water)
• Fizzing/Effervescence can be observed

Question 6

State the trends going down group 1

Answer 6

• Melting Point Decreases
• Reactivity increases
• Density increases (except potassium)

Question 7

Why does reactivity of alkali metals increasing going down the group.

Answer 7

Atomic size of elements increase, Increase in number of electron shells. → Attraction between positively charged nucleus and valence electrons decreases as valence electrons are further away from the nucleus. → Easier to lose the valence electron going down the group.

Question 8

How does reactivity change when going down group 17?

Answer 8

Reactivity decreases

Question 9

State physical properties of Halogens

Answer 9

• Low melting and boiling points
• are coloured elements
• cannot conduct electricity

Question 10

Colour and state of flourine in r.t.p

Answer 10

• Pale yellow
• Gas

Question 11

Colour and state of chlorine in r.t.p

Answer 11

• Greenish-Yellow
• gas

Question 12

Colour and state of Bromine in r.t.p

Answer 12

• Reddish Brown
• Liquid

Question 13

Colour and state of Iodine in r.t.p

Answer 13

• Purple Black (Brown Solution)
• Solid

Question 14

Colour and state of Astatine in r.t.p

Answer 14

• Black
• Solid

Question 15

Why does reactivity decreases down group 17?

Answer 15

Atomic size of elements increase, Increase in number of electron shells. → Attraction between positively charged nucleus and valence electrons decreases as valence electrons are further away from the nucleus. → More difficult to gain an electron to obtain a stable noble gas configuration

Question 16

Why does m.p and b.p increases down group 17?

Answer 16

Group 17 elements are a covalent substance and exists as simple discrete molecules.→ As the mass of halogens increases down the group, the intermolecular forces of attraction are strengthened. → More energy is needed to overcome the stronger intermolecular forces of attraction down the group. → Going down the group, elements change from gas to liquid then to solid

Question 17

What are the similarities between hydrogen and alkali metals?

Answer 17

• Atoms of these elements lose 1 electron to form positive ion of 1+ charge.
• Atoms of these elements have one valence electron.

Question 18

What are the differences between hydrogen and alkali metals?

Answer 18

• Atoms of hydrogen can gain electron to form anion (H−) whereas atoms of Group 1 lose electron to form cation.
• Hydrogen exists as a gas whereas Group 1 elements exist as solid state at room temperature and pressure.
• Hydrogen does not conduct electricity whereas Group 1 elements conduct electricity well.
• Hydrogen is colourless gas, Group 1 are shiny and silvery solids.