Periodicity

repeated patterns in periodic table

row across periodic table

column down periodic table

atomic number

outer electrons in same shell

same number of outer electrons

attractions of electrons to nucleus increases

• repulsion is greater • electrons pulled less strongly towards nucleus

• same number of shells • more protons electrons • pulled more strongly toward nucleus • radius decreases across period

• more protons • number of shells increases • electrons repelled more • less attraction to nucleus • atomic radius increases down group

• metallic ions lose electrons so have one fewer shell so size decreases non-metal • ions gain electrons so have one more shell so size increases

• protons increases • shells increase • ionic size increases because electrons held less tightly

• more protons • same number of shells • greater attraction to nucleus

• more protons • more shells • less attraction of electrons to nucleus

ability to attract a pair of electrons towards self in covalent bond

reactive group of non-metals in group 17

very unreactive family of non-metals found at extreme right-hand side in group 18

reactive group of metals in group 1

metals which make up first and second row of f block

have characteristics of both metals and non-metals

• increases • effective nuclear charge increases • increase in attraction between outer electrons and nucleus • more difficult to remove electrons

• decreases • electron is removed from energy level furthest from nucleus • nuclear charge increases • effective nuclear charge about the same (shielding of inner electrons) • increased distance between electron and nucleus reduces attraction

• electron removed from group 16 element comes from doubly occupied p orbital • easier to remove as it is repelled by partner

p orbitals have higher energy than s orbitals