Step I – Write each symbol with valency Positive ion is written first. Step II – Inter change the valencies positive ion is write first. Step II – Inter change the valencies ignoring the (+) and (-) signs. Step II – Inter change the valencies ignoring the signs. Step II – Interchange the valencies ignoring the signs. Step II – Inter change the valencies and ignoring (+) and (-) signs Step II – Inter change the valencies and ignoring positive and negative signs. Step 1 – Write each symbol with valency Positive ion first Step II – Inter change the valencies and ignoring the +ve and -ve signs Step 1 – Write each symbol with valency Positive ion is written first Step II – Inter change the valencies and ignore the signs Step 1 – Write each symbol with its valency positive ion is written first Write the chemical formula of the following compounds in a step-by-step manner – Negative radical (Bicarbonate), (Nitrate) Radical “is group of atoms of elements that behaves like a single unit & show valency.” Ion “is an atom or a group of atoms carrying a positive or negative charge due to loss or gain of electrons.” e.g. State which of the following ions or radicals given below of non-metallic elements exhibit-valency: 1 –, 2 – & 3 –ĭifferentiate between the terms – ‘Ion’ & ‘radical’ with suitable examples. State the variable valency of the following metals – Metals have positive valency 1, 2 or 3 Valency ofĬertain metals exhibit variable valencies which include valencies: 1 +, 2 +, 3 + & 4 +. State the valencies of the following metallic elements – Variation in this gain or loss results in ‘variable valency’.ĬuCl is named as cuprous chloride (lower valency)ĬuCl 2 – Cupric chloride (higher valency) has variable valency reason for variable valency Valency is – the number of electrons lost or gained from the outer shell of an atom of an element – during chemical reaction. Variable valency : “When an element has more than one valency, its valency is called variable valency.” Copper exhibit valency ‘1’ and ‘2’ i.e. Give a reason for the same & name the compound CuCl & CuCl 2. Hence is cation Mg 2+ has valency 2 +.Įxplain the term ‘variable valency‘ Copper having electronic configuration 2, 8,18,1 exhibits variable valency.

there are 2 valence electrons which Mg can lose and achieve stable configuration of nearest noble gas Neon.

Valency of magnesium is 2 +, Mg Electronic configuration of Mg is 2, 8, 2 i.e. Valency of atom nitrogen is 3, as it combines with 3 atoms of hydrogen. Compound water H 2O, two atoms of hydrogen combine with one atom of oxygen to form water. Valency is the number of hydrogen atoms which combine with (or displace) one atom of the element forming a compound. With reference to water & ammonia as compounds respectively, state the valency of oxygen & nitrogen. Hence symbol of calcium is ‘Ca’ and symbol of copper or cuprum (Latin name of copper) is ‘Cu’.ĭefine the term ‘valency’. “Symbol of an element is the ‘first letter’ or the ‘first letter and another ‘letter’ of the English name or Latin name of the element”.Īs the name calcium and copper start with same letter of English alphabet ‘C’ so another letter from the name of the element is added to ‘C’. Symbol is a short form or abreviated name – of the element. State a reason why – the symbol of calcium is ‘Ca’ & of copper is ‘Cu’ Chemistry ICSE Class 8 Important Questions Chapter 5 Language of ChemistryĮxplain the term ‘symbol’.

Cuprum latin