periodic table and energy

the repeating pattern of behaviour across a period

in order of increasing atomic number

chemical properties

the energy recquired to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous ions with a 1+ charge

the distance between the nucleus and the electron being removed

the number of protons in the nucleus

the amount of shells between the nucleus and the electron being removed

• atomic radius decreases • electron shielding remains the same • nuclear charge increases therefore nuclear attraction increases- more energy is required to remove the outermost electron

• atomic radius increases • nuclear charge increases (but this is outweighed) • electron shielding increases therefore nuclear attraction decreases, less energy is required to remove the outermost electron.

Be’s outermost electron is in a 2s orbital, B’s outermost electron is in a 2p orbital - which is further away from the nucleus. Therefore B’s outermost electron experiences less nuclear attraction, therefore slightly less energy needs to be put in to remove it.

both N and O have their outermost electron in a 2p orbital. However oxygen has 2 electrons paired up in one 2p orbital. Paired electrons in oxygen repel one another, and therefore less energy is required to remove.

between Be and B between N and O

the strong electrostatic attraction between positive metal ions and negative delocalised electrons

• conduct electricity - mobile delocalised electrons • insoluble in water • strong metallic bonds cause high melting and boiling points

the number of delocalised electrons, the more delocalised electrons, the more conductive.

• larger ratio of protons to electrons • atomic radius decreases therefore nuclear attraction increases

electrostatic attraction between positively and negatively charged ions

diamond graphite graphene silicon

• each carbon atom makes 4 strong covelant bonds to 4 other carbons • the shape around each carbon is tetrahedral bond angle 109.5 • high melting point - strong covelant bonds • insoluble in water • does not conduct electricity- no delocalised electrons, all electrons used in bonding

• each carbon makes 3 strong covelant bonds to other carbons • carbons are arranged in a hexagonal arrangment, trigonal planar shape, bond angle 120 • 4th electron is delocalised • insoluble • high melting point - strong covelant bonds WITHIN layers • soft as weak london forces BETWEEN layers • can conduct electricity due to delocalised electrons

• each carbon makes 3 bonds to another carbon • shape is trigonal planar 120 bond angle -single layer of graphite • conducts electricity and heat • insoluble • very strong

• each silicon atom makes four bonds • tetrahedral shape bond angle 109.5 • high melting point due to strong covelant bonds between atoms • insoluble • does not conduct electricity, all outershell electrons used in bonding

used in transistors, as pure silicon does not conduct electricity it must be mixed with a small amount of impurities.

GROUP 2: Li, Be GROUP 3: Na, Mg, Al