Group 3 A2 Flashcards Preview

AS/A2 Chemistry - Inorganic > Group 3 A2 > Flashcards

Flashcards in Group 3 A2 Deck (13):
1

All the elements in Period 3 except ______ and _______ combine directly with oxygen to form oxides.

except chlorine and argon

2

Give the equation for sodium combining with oxygen

4Na(s) + O2(g)  2Na2O(s)

3

Give the equation for magnesium combining with oxygen

2Mg(s) + O2(g)  2MgO(s)

4

Give the equation for aluminium combining with oxygen

4Al(s) + 3O2(g)  2Al2O3(s)

5

Give the equation for silicon combining with oxygen

Si(s) + O2(g)  SiO2(s)

6

Give the equation for phosphorous combining with oxygen

P4(s) + 5O2(g)  P4O10(s)

7

Give the equation for sulfur combining with oxygen

S(s) + O2(g)  SO2(g)

8

What is unique about the structure/bonding of Al2O3?

Mostly ionic, but with significant covalent character.

9

Na2O, Al2O3 and MgO are ____ oxides and hence have a ______ melting point.

Na2O, Al2O3 and MgO are ionic oxides and hence have a high melting point.

10

Why do MgO and Al2O3 have a higher melting point than Na2O?

The charges are higher, resulting in a stonger attraction between the ions. Also Al2O3's bonding contains a lot of covalent character.

11

Are ionic oxides acidic/basic? State the equation.

Basic: O2-(aq) + H2O(l)  2OH-(aq)

12

Are covalent oxides acidic/basic? State the equation.

Acidic: MO(s) + H2O(l)  MO(OH)-(aq)+ H+(aq)

13

Why are covalent oxides acidic?

They do not contain ions, but have a strongly positive dipole on the atom which is not oxygen. This attracts the lone pair on water molecules, releasing H+ ions.