Four blocks of elements in the periodic table. 1 – s block elements. Elements of groups 1 and 2 each possessing one and two electrons respectively in the s orbital of their outermost orbits are together known as s block elements. Example : Na: 1s2 2s2 2p6 3s1 Mg: 1s2 2s2 2p6 3s2 Characteristics of
Ionization energy (or potential) of an element is defined as “The amount of energy required or needed to remove an electron from the neutral gaseous atom to form unipositive ion , for example Na → Na+ + e– + energy This is measured in electron volts per atom or kJ mol-1. For example IE of
Shapes of s and p orbitals s orbital can have only one possible orientation (as it’s m quantum is zero), it is spherical in shape i.e., in an s orbital the electron distribution is symmetrical around the nucleus in all directions. However the size of s orbital depends on principal quantum number. Large n means