Question

Find valency of an all elements.

Answer 1

tell the elements first

Answer 2

You may assume that the valences of the elements are those that can be derived by looking at the groups (columns) of the periodic table. While these are the most common valences, the real behavior of electrons is less simple.

Here is a table of element valences. Remember that an element's electron cloud will become more stable by filling, emptying, or half-filling the shell. Also, shells don't stack neatly one on top of another, so don't always assume an element's valence is determined by the number of electrons in its outer shell.
Table of Element Valences

NumberElementValence1Hydrogen(-1), +12Helium03Lithium+14Beryllium+25Boron-3, +36Carbon(+2), +47Nitrogen-3, -2, -1, (+1), +2, +3, +4, +58Oxygen-29Fluorine-1, (+1)10Neon011Sodium+112Magnesium+213Aluminum+314Silicon-4, (+2), +415Phosphorus-3, +1, +3, +516Sulfur-2, +2, +4, +617Chlorine-1, +1, (+2), +3, (+4), +5, +718Argon019Potassium+120Calcium+221Scandium+322Titanium+2, +3, +423Vanadium+2, +3, +4, +524Chromium+2, +3, +625Manganese+2, (+3), +4, (+6), +726Iron+2, +3, (+4), (+6)27Cobalt+2, +3, (+4)28Nickel(+1), +2, (+3), (+4)29Copper+1, +2, (+3)30Zinc+231Gallium(+2). +332Germanium-4, +2, +433Arsenic-3, (+2), +3, +534Selenium-2, (+2), +4, +635Bromine-1, +1, (+3), (+4), +536Krypton037Rubidium+138Strontium+239Yttrium+340Zirconium(+2), (+3), +441Niobium(+2), +3, (+4), +542Molybdenum(+2), +3, (+4), (+5), +643Technetium+644Ruthenium(+2), +3, +4, (+6), (+7), +845Rhodium(+2), (+3), +4, (+6)46Palladium+2, +4, (+6)47Silver+1, (+2), (+3)48Cadmium(+1), +249Indium(+1), (+2), +350Tin+2, +4