6 PERIODIC TRENDS

list of elements arranged in order of increasing proton (atomic) numbers.

7 periods and 18 groups of elements.

Elements from Group 3 to 12 are known as transition metals or transition metals

number of valence electrons

number of principal quantum shells

Step-like line from the top of Group 13 to the bottom of Group 16 divides the elements into metals and non-metals.

Metals form basic oxides.

Non-metals form acidic oxides.

Metalloids form amphoteric oxides.

Elements in the Group: - Have the same number of valence electrons - Have the same chemical properties - Forms ions with the same charges - Form compounds with similar formulae

Down the Group - Atomic size increase - Number of principal quantum shells increases - Reactivity and metallic character increases down a group of metals

group 1 elements

• Relatively soft and can be cut easily with a knife. • Low melting and boiling points (compared to other metals). • Good conductors of heat and electricity.

• _M_elting points and boiling points decrease down the group. • _A_tomic radii of Group 1 metals increase down the group. • _D_ensity of alkali metal increases down the group. MAD

Each Group 1 metal has an increase of 1 core electron shell, hence the shielding effect increases down the group

The protons in the nucleus exert an attractive force on the negatively charged electrons. its number is the same as proton/atomic number

basically more core shells mean more INNER ELECTRONS, the OUTER ELECTRONS in the outer shells will have a weaker nuclear attraction

they lose their valence electron more easily cuz atomic radii increases by 1 core electron shell -> valence electrons become** further** from the nucleus -> shielding effect increase -> it increases more than the nuclear charge -> effective nuclear charge decreases -> electrostatic forces of attraction between the nucleus and the valence electron becomes weaker. Less energy is required to remove

the atomic mass(proton number) increases faster than the atomic volume.(no. of shells)

Less dense than water: Li, Na and K Denser than water: Rb and Cs

• Size of metal cation increases down the group. • Electrostatic forces of attraction between sea of delocalised electrons and metal cations decreases. • Metallic bonding weakens down the group, less energy required to break the weaker metallic bonds,

• Group 1 elements are the most reactive metals in the Periodic Table. • They have similar chemical properties because all the elements have similar electronic configuration, that is, one electron in their outermost shell. • The Group I metals are very reactive. They react rapidly with air and vigorously with water. They are kept under oil to prevent them from coming into contact with air and water. • They are called alkali metals as they react readily with water to form alkalis.

All the alkali metals react with cold water to form alkalis (soluble metal hydroxides) and hydrogen gas.

as density increases, melting and boiling points tend to decrease. (idk if need memorise all the numbers but this the trend other than potasssium)