Chemistry: Group 1 Alkali metals and Group 7 halogens

What type of solutions do group 1 elements form when reacted with water?

alkaline solutions.

what are the properties of group 1?

They are all soft metals which can easily be cut with a knife

They have relatively low densities and low melting points

They are very reactive (they only need to lose one electron to become highly stable)

What is the equation of group 1 reaction with water?

Group 1 metal + water ⟶ metal hydroxide + hydrogen

      2M (s) + 2H₂O (l) ⟶ 2MOH (aq) + H₂ (g) 

What is the trend of alkali metals reactions with water?

The reactions of the alkali metals with water get more vigorous as you descend the group

What do alkali metals react with oxygen to form? What does this mean for alkali metals physical appearance when exposed to air?

oxygen in the air forms metal oxides, which is why the alkali metals tarnish when exposed to the air

What happens with tarnish as you go down group 1?

tarnish more rapidly

What is the trend of alkali metals softness?

getting softer as you move down the group

Why are halogens dangerous?

they are poisonous

What are all halogens molecules?

diatomic

What is the trend in the colour and melting/boiling point of the elements in group 7 and why?

Darker in colour as go down the group, reflective of the increase in melting/boiling point as well, due to increasing intermolecular forces as the atoms become larger, so more energy is required to overcome these forces

What is the trend in the density of the elements in group 7?

increase as go down the group

What is the trend in the reactivity of the elements in group 7?

decreases as go down the group as there are weaker electrostatic forces of attraction going down the group as the outer shell is further from the nucleus, making it harder to attract electron to complete full outer shell.

How does the physical state of elements in group 7 change going down the group?

goes from gas → liquid → solid

What do halogens react with metals to form?

ionic compounds which are metal halide salts

What do halogens react with non-metals to form?

simple molecular covalent structures

What is the halogen displacement reaction?

more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide. (remember top is most reactive!)