easechemistry

Q: Why cation is smaller than its parent atom ? An atom has equal number of positive protons and negative electrons. This atom becomes cation after losing one or more electrons.Due to this imbalance between negative charge electrons and positive charge protons. Protons in Nucleus exerts more force of attraction on electronic shells. As a result cation becomes smaller than its parent atom. for example if we take Na atom it has 11 electrons in shells and 11 protons in nucleus. To become cation, Na loses its one electron from outermost shell. So one electron become less than proton , so more force of attraction exerts on electrons and size of cation becomes small. Q: Why anion is greater than its parent atom? An atom has equal number of positive protons and negative electrons. Atom becomes anion after gaining one or more  electrons. Due to this imbalance between negative charge electrons and positive charge protons.Nuclear charge ( charge due to protons) exerts less attrac

https://youtu.be/I-01PNEakZg  ( How to calculate oxidation number/state of elements in neutral compound and polyatomic ions? Oxidation Number/ Oxidation State: Definition : Oxidation number or oxidation state is apparent charge on element in a compound or polyatomic ion. Explanation:  oxidation number or state of certain elements are assigned by following rules. Oxidation number or state of elemental forms like H2, O2, P4, S8 Cu, Al etc are always "zero" Elements of IA(Alkali metals) group is always +1 Element of IIA (Alkaline earth metals) is always +2 Elements of VIIA (halogen) is usually -1.Positive if attached to oxygen. Florine is always -1.  Oxygen in normal oxide is -2 (in peroxide is -1) Hydrogen is +1 attached with non metal and -1 when attached with metals. The sum of all the oxidation number of all atoms in a neutral compound is "Zero" The sum of all the oxidation number of all atoms in a polyatomic ion is equal to change o