Characteristics of a Group
Valence electrons, valency, atomic size, ionization energy, metallic character, electron-positivity, electron-negativity and reactivity are the characteristics of groups. This note describes about variations in different properties of a group in a periodic table.
Summary
Valence electrons, valency, atomic size, ionization energy, metallic character, electron-positivity, electron-negativity and reactivity are the characteristics of groups. This note describes about variations in different properties of a group in a periodic table.
Things to Remember
- Valence electrons, valency, atomic size, ionization energy, metallic character, electron-positivity, electron-negativity and reactivity are the characteristics of groups.
- The atomic radius of the element (i.e. atomic size) lying in a group increases as we go up from top to bottom in a group.
- The energy, which is required to pull out the most loosely, held electron in an atom is called ionization energy.
- After losing their outer electron, an atom becomes electro-positively charged.
- After gaining its electron, an atom becomes electro-negative.
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Subjective Questions
Q1:
Explain the procedure of preparing ledger account.
Type: Short Difficulty: Easy
Q2:
The following transactions are extracted from the books of a trader:
- Started business with cash Rs.60,000.
- Cash deposited in the bank Rs.50,000.
- Goods purchased from Ramesh for Rs.10,000 and paid by cheque Rs.3,000 in part.
- Cash sales made Rs.800.
- Paid for salary Rs.4,000 and for rent Rs.2,000 by cheque.
- Received commission of Rs.2,500.
Required: Cash a/c and Bank a/c
Type: Short Difficulty: Easy
Q3:
The following transactions are extracted from the books of Mr. Prithivi Poudel:
- Purchased office furniture for Rs.7,000 from Fine Furniture Centre and paid by cheque Rs.2,000 in part.
- Cash received from Mr. Jatan Joshi Rs.2,300 and allowed discount to him Rs.200.
- Cash purchases made Rs.700.
- Received rent through cheque Rs.2,500.
- Paid for interest Rs.600.
Required: Cash a/c and Purchase a/c
Type: Short Difficulty: Easy
Videos
Procedures of Preparation Ledger Account

Characteristics of a Group
Characteristics of groups
- Valence electrons: The number of valence electrons lying in-group is always same i.e. the elements lying in group IA has one valence electron whereas the elements of group VII A have 7 valence electrons.
- Valency: The combining capacity of the elements (i.e. valency) lying in a group is always same. Example: valency of group IA elements is +1 whereas the valency of group VII A elements is -1.
- Atomic size: The atomic radius of the element (i.e. atomic size) lying in a group increases as we go up from top to bottom in a group. It is so because on going down in a group the number of shells successively increases.
- Ionization energy: The energy, which is required to pull out the most loosely, held electron in an atom is called ionization energy. In a group, on going from top to bottom, the ionization energy decreases as the nucleus apply only less energy to pull outer electron because of longer atomic radius.
- Metallic character: The metallic character of the elements lying in a group increases on going from top to bottom in a group. For e.g.: in-group VA the first element is nitrogen, a non-metal and the last element is bismuth, a metal.
Element Atomic Number Characters Nitrogen (N) 7 Non Metal Phosphorous (P) 15 Non Metal Arsenic (As) 33 Metalloid Antimony (Sb) 51 Metalloid Bismuth 83 Metal - Electro-positivity: After losing their outer electron, an atom becomes electro-positively charged. So in a group, the electro-positivity of the element increases on going from top to bottom as they can lose their outer electron easily because of longer radius.
- Electro-negativity: After gaining its electron, an atom becomes electro-negative. So, the electron gaining capacity of an atom decreases along with the increase in its atomic size. So, electro-negativity of an element decreases as we go from top to bottom.
- Reactivity: In group IA,II A and III A, the elements have the tendency to lose electrons. Therefore, the electron losing capacity increases because of longer atomic radius as we go from up to down. Therefore, reactivity increases on going from top to bottom. But in group VA,VIA and VII A, the elements have the tendency to gain electrons. So, the electron gaining capacity reduces along with the increase in atomic size. So, in these groups, the reactivity decreases as we go from top to bottom.
Lesson
Classification Of Elements
Subject
Science
Grade
Grade 10
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