Chem: Groups + Displacement

What are Group 1 elements known as?

The alkali metals.

What products are formed when Group 1 metals react with water?

A metal hydroxide solution (alkaline) and hydrogen gas (which causes fizzing).

What is the word and balanced symbol equation for the reaction of sodium with water?

Word: sodium + water -> sodium hydroxide + hydrogen; Symbol: 2Na(s) + 2H2O(l) -> 2NaOH(aq) + H2(g).

What oxides are formed when lithium, sodium, and potassium react with oxygen in the air?

Lithium forms lithium oxide (Li2O); sodium forms sodium oxide (Na2O) and sodium peroxide (Na2O2); potassium forms potassium peroxide (K2O2) and potassium superoxide (KO2).

How does reactivity change as you go down Group 1?

Reactivity increases down Group 1 (potassium is more reactive than sodium, which is more reactive than lithium).

Why do Group 1 metals become more reactive as you go down the group?

All Group 1 metals have 1 outer electron. Down the group, atoms get bigger so the outer electron is further from the nucleus, reducing attraction and making the electron easier to lose.

What are Group 7 elements known as?

The halogens.

Describe the appearance and state of chlorine, bromine, and iodine at room temperature.

Chlorine is a poisonous green gas; bromine is a poisonous red-brown liquid (gives off orange vapour); iodine is a dark grey crystalline solid (gives off purple vapour when heated).

How do melting points, boiling points, and color change going down Group 7?

Elements get darker in colour and have higher boiling points as you go down Group 7.

Why does reactivity decrease as you go down Group 7?

Group 7 atoms have 7 outer electrons and need to gain 1 electron. Down the group, the atomic radius increases, making it harder for the nucleus to attract an extra electron.

What is a displacement reaction in Group 7 chemistry?

A reaction where a more reactive halogen "pushes out" (displaces) a less reactive halogen from a compound.

What happens when chlorine water is added to potassium bromide and potassium iodide solutions?

Chlorine displaces bromine to form an orange solution (Br2), and displaces iodine to form a brown solution (I2).

Define oxidation and reduction in terms of electron transfer.

Oxidation is the loss of electrons; reduction is the gain of electrons (OIL RIG).

In halogen displacement reactions, which species acts as the oxidising agent and which acts as the reducing agent?

The more reactive halogen accepts electrons and gets reduced (oxidising agent); the halide ion donates electrons and gets oxidised (reducing agent).

What is a redox reaction?

A reaction where reduction and oxidation happen simultaneously at the same time.