Periodic table Definition
1. Periods: The horizontal rows of the periodic table are called periods.
Groups: The vertical columns of the periodic table are called groups.
2. Electronegativity: The tendency of an atom to attract electrons towards itself is called electronegativity.
3. Ionization Energy: The energy required to remove the outermost electron from an atom is called ionization energy.
4. Alkali metals: Elements of group ⅠA of the modern periodic table are called alkali metals.
Ex- Sodium( Na) , Potassium ( K ).
5. Alkaline Earth Metals: Elements of group Ⅱ A of the modern periodic table are called alkaline earth metals.
Ex: Calcium (Ca), Magnesium ( Mg).
6. Transition Elements: Any of the metallic elements within groups 3 to 12 in the modern periodic table that have an incomplete inner electron shell and that serve as transitional links between the most and the least electropositive in a series of elements are called transition elements.
7. Rare-Earth elements: The elements starting from certain cerium(Ce) to lutetium(Lu) of the sixth period of the periodic table occur rarely in nature. So, they are called rare-earth elements.
8. Transuranic elements: The 13 radiations elements after uranium in the seventh period of the periodic table have been prepared artificially in the laboratory. They are called transuranic elements.
Ex: Neptunium( Np), Plutonium( Pu).
Sub-groups: Each group fromⅠ to Ⅶ is subdivided into two parts. These parts are called sub-groups.
9. Halogens: Elements of group Ⅶ A of the modern periodic table are called halogens.
Ex: Fluorine(F), Chlorine(Cl)
1. Noble or Inert Gases: Elements of group Ⅷ A of the periodic table are called noble or inert gases.
Ex: Helium(He), Neon(Ne)
11. Coinage metals: Elements of group 1B of the modern periodic table are called coinage metals.
Ex: Copper(Cu), Silver(Ag), Gold(Au)
Rogue element: The element which exhibits the dual properties is called the rogue element.
Laws:
Mendeleev’s Periodic Law: The physical and chemical properties of all elements are periodic functions according to their weight.
Modern Mosely Periodic Law: The physical and chemical properties of all elements are periodic functions according to their atomic number.
Dobereiner’s Law of Triads: If the three e Udlements having similar properties are arranged in order of their increasing atomic weights, then the atomic weight of the middle one will be the Arithmetic mean of the atomic weight of the other two. This is called Dobereiner’s Law of Triad.
Octave Law: If the elements are arranged in order of their increasing atomic weights then the properties of every eighth element will be similar to the properties of the first one. This is known as Newland’s law of octaves.
Short Questions on Periodic table
How many periods and groups are there in Mendeleev’s periodic table?
ANS: 7 periods and 9 groups.
How many periods and groups are there in the Modern Periodic Table?
ANS: 7 periods and 18 groups.
what is the name of the element which belongs in the 1st and 7th group?
ANS: Hydrogen.
Which element is called Rogue element and why?
ANS: Hydrogen is called the Rogue element.
The properties of Hydrogen exhibit similarities as well as dissimilarities with the properties of alkali metals and with those of halogens. Due to this dual nature of hydrogen, Mendeleev called hydrogen a Rogue element.
Which element has the highest electronegativity?
ANS: Fluorine(F).
What is the position of an element whose atomic number is 13?
ANS: 3rd period and 3rd group.
What is the name of an inert element closest to chlorine?
ANS: Argon.
In which group do inert gases belong?
ANS: Inert gases belong to the zero group.
Which group is known as zero group?
ANS: The last group of the periodic table in which inert gases belong is called the zero group.
Arrange I, F, Cl, Br in increasing order of electronegativity.
ANS: I < Br < Cl < F.
Ionic and Covalent Bonding Definition
Chemical Bonding: The force of attraction or the bond which binds the atom together in a molecule of an element, compound or ionic cluster is called chemical bonding.
Electrovalency: The number of electrons donated or accepted by the valence shell of an atom of an element to achieve the stable electronic configuration is called electro valency.
Covalency: The number of electron pairs that an atom shares with one or more atoms of the same or different kind to achieve a stable electronic configuration of nearest inert gas is called covalency.
Electrovalent Bond: The bond formed due to the transferring of one or more electrons between the atoms of the element is called an electrovalent Bond.
Covalent Bond: The bond formed due to the mutual sharing of one or more electron pairs between the atoms of the same or different elements is called a covalent bond.
Electrovalent Compound: The compound formed due to the transferring of one or more electrons between atoms of the element is called an electrovalent compound.
Ex- NaCl, CaO.
Covalent Compound: The compound formed due to the mutual sharing of one or more electron pairs between the atoms of the same or different elements is called a covalent compound.
Ex- CH4, HCl
Difference between Eelectrovalent compound and covalent compound
IDENTIFY THE FOLLOWING AS ELECTROVALENT OR COVALENT COMPOUNDS
