2.5 The Periodic Table- Groups 2 and 7

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2.5 The Periodic Table- Groups 2 and 7.

-First Ionization Energy- Decreases down the group because as you move down the group the number of energy levels between the nucleus and the outer most electrons. This acts as a barrier between them and means that the charge of the nucleus has less of an effect on the electrons making it easier to remove them. Also as the number of energy levels increases so does the distance between the nucleus and the outer most electrons. This also makes the charge of the nucleus affect the outer most electrons less making them easier to remove. Nuclear charge does not effect this as much as shielding and distance.

-Group 2 with oxygen- group two elements burn in oxygen to form solid metal oxides. Reactivity with oxygen increases down the group because the electrons that reacts are not as attracted to nucleus making them easier to remove.

-Group 2 with chlorine- group two elements burn in chlorine gas to form metal chlorides. Reactivity with chlorine increases down the group but not as obviously as with oxygen.

-Group 2 with water- beryllium does not react with water, magnesium does very slowly to form magnesium oxide and hydrogen. Strontium, barium and radium all react with water to form metal hydroxides and hydrogen.

-Group 2 oxides with water- beryllium does not react, magnesium only reacts slightly. Strontium, barium and calcium oxide all react to form metal hydroxide.

-Group 2 oxides with dilute acid- Hydrochloric acid= chlorine salt and water. Nitric acid (HNO3) = nitrate salt and water.

-Group 2 hydroxides with dilute acid- forms metal chloride and water.

-Group 2 hydroxide solubility- increases down the group.

-Group 2 sulfate solubility- decreases down the group.

-Group 2 carbonates- become more stable to heat as you go down the group (must be heated more strongly before they decompose).

-Group 2 nitrates- become more stable to heat as you go down the group (must be heated more strongly before they decompose).

-Flame Test-dip a nichrome wire in concentrated hydrochloric acid. Dip this in the element your testing and place in Bunsen burner. Record the colour.

Lithium= crimson

Sodium= Yellow/Orange

Potassium= Lilac

Calcium= Red/Yellow

Strontium= Red

Barium= Apple Green