topic 6 - Group 1 periodic table

Explain why some elements can be classified as alkali metals (group 1), halogens (group 7) or noble gases (group 0), based on their position in the periodic table

because they have the same number of electrons in their outer shell (position in the periodic table determines this), therefore they have the same chemical properties

6.2 Recall that alkali metals (a) are soft (b) have relatively low melting points.

Alkali metals are soft and have relatively low melting points.

6.3 Describe the reactions of lithium, sodium and potassium with water.

Lithium, sodium and potassium in group one react vigorously with water to create an alkaline metal hydroxide and hydrogen.

Describe the pattern in reactivity of the alkali metals, lithium, sodium and potassium, with water; and use this pattern to predict the reactivity of other alkali metals

lithium - floats then begins to steam and turn pink, gives off hydrogen/turns into an alkali

sodium: floating,melting-gives off hydrogen, popped orange flame and exploded

potassium:lilac flame,metal mive and pop/explode, propelled by gas
As shown by the way the reactions with water become more vigorous down the group, the reactivity of all alkali metals increases down the group.

Explain this pattern in reactivity in terms of electronic

configurations

activity increases as u go down the group

atoms of each element gets larger going down the group

this means that the outer shell electrons gets further away from the nucleus and is shielded by more electron shells

further an electron is from the positive nucleus the easier it can be lost in reaction