Which of the following physical properties decreases across the periodic table ____________
A. Ionization potential B. Electron affinity C. Electron negativity D. Atomic radius E. Electro-positive reaction
Correct Answer: D
Explanation
lonization energy is the energy required to remove the valence electron(s) (most loosely, bound electron(s)) from atoms in the ground state; it increases progressively across the period (from left to right) and decreases down the group (top to bottom) - Electron affinity is the energy released in adding an electron to a neutral atom in the gas phase; it is a measure of the readiness of an atom to gain electron; it increases across the period from left to right and decreases down the group from top to bottom - Electronegativity is a measure of the relative tendency with which the atoms of an element attract the elec. tron(s) in a chemical bond towards itself. It increases across the period and decreases down the group - Atomic radius is half the distance between the nucleus of two covalently bonded atoms of non - metallic elements. It decreases from left to right across the period and increases down the group