The vertical columns of the periodic table are called groups. 1 2 The horizontal rows are called periods 3 4 5 6 7

What is the link between the group number of an element and how the element reacts? Reactions of the alkali metals (group 1 elements) Reactivity of the alkali earth metals (group 2 elements) Reactivity of the halogens (group 7 elements) Uses of the noble gases (group 0 elements)

Group 1 and 2 elements become more reactive as they go down the group. This is because: Group 1 and 2 elements want to lose electrons. As they go down the group, their outermost electrons get further from the positive nucleus. There is less attraction between the negative electron and the positive nucleus. It is easier for the electron(s) to leave the atom.

Group 7 elements become more reactive as you go up the group. This is because: Group 7 elements want to gain electrons. As they go down the group, their outermost electrons get further from the positive nucleus. There is less attraction between the negative electron and the positive nucleus. It is harder for the atom to gain an electron.

Group 1: The alkali metals Least reactive Low density Very reactive They get more reactive as they go down the group as there is less attraction between the outer electron and the nucleus so it is easier for the electron to leave the nucleus. Their melting point decreases going down the group. They react with water to produce metal hydroxide and hydrogen. Metal + water  Metal hydroxide + hydrogen The react with halogens to make a metal halide. Metal + halogen  metal halide Highest melting point Most reactive Lowest melting point

Group 7: The halogens F2(aq) + 2KI(aq)  2KF(aq) + I2(aq) Most reactive Low melting point Poor conductors of heat and electricity They form 1- ions They get less reactive going down the group. This is because halogens gain electrons. As you go further down the group, the nucleus is further from the outer shell, so there is less attraction between it and the electron it wants to gain. Their melting point increases going down the group. Lowest melting point More reactive halogens displace less reactive halogens F2(aq) + 2KI(aq)  2KF(aq) + I2(aq) Least reactive Highest melting point Br2(aq) + 2KCl(aq)  NO REACTION

Transition elements They share many properties: Good conductors of electricity and heat. Hard and strong High density High melting point (except mercury) Quite unreactive Form ions with different charges (e.g Fe2+ and Fe3+) Form coloured compounds

1) Which group is this atom in? b) 2 c) 3 d) 12

2) How many electrons does boron have?

3) How many electrons does barium have in its outer shell?

4) Which of the following elements are unreactive (pick 2 answers)? a) nitrogen b) oxygen c) fluorine d) neon e) lithium f) helium

5) What is the electron configuration for chlorine? b) 8,7,2 c) 8,8,1 d) 2,7,8

6) Which element has 4 electrons in its outer shell? a) Helium b) Beryllium c) Carbon d) Potassium

7) Which two elements would react in a similar way? Lithium and Beryllium Gold and chlorine Lithium and sodium Hydrogen and helium

8) In which group would you find the unreactive elements? 1 2 3

9) How many elements are in period 1? 2 8 18 32

10) How many electrons does iodine have in its outer shell? 5 6 7 8

1) Which group is this atom in? b) 2 c) 3 d) 12

2) How many electrons does boron have?

3) How many electrons does barium have in its outer shell?

4) Which of the following elements are unreactive (pick 2 answers)? a) nitrogen b) oxygen c) fluorine d) neon e) lithium f) helium

5) What is the electron configuration for chlorine? b) 8,7,2 c) 8,8,1 d) 2,7,8

6) Which element has 4 electrons in its outer shell? a) Helium b) Beryllium c) Carbon d) Potassium

7) Which two elements would react in a similar way? Lithium and Beryllium Gold and chlorine Lithium and sodium Hydrogen and helium

8) In which group would you find the unreactive elements? 1 2 3

9) How many elements are in period 1? 2 8 18 32

10) How many electrons does iodine have in its outer shell? 5 6 7 8