CHEMISTRY [1 Mark Question Answer]

Hydrochloric acid = HCl
Ferrous sulphate = FeSo4
Zinc sulphate= ZnSo4
Calcium oxide = CaO
Silver nitrate = AgNO3
Copper oxide = CuO

H2SO4 = Sulphuric Acid
NaOH = Sodium hydroxide
Na2CO3 = Sodium Carbonate
CuSO4 = Copper Sulphate
NaHCO3 = Sodium Bicarbonate
CH4 = Methane

A compound is a substance that results from a combination of two or more different chemical elements, in such a way that the atoms of the different elements are held together by chemical bonds that are difficult to break.

Three examples of each molecule which has different kind of atoms are :-
Carbon Dioxide
Water
Sodium Chloride

Three examples of each molecule which has similar kind of atoms :-
Hydrogen.
Oxygen.
Nitrogen.

The smallest particle of a substance that has all of the physical and chemical properties of that substance

An element is a pure substance that cannot be broken down by any physical or chemical means into simpler substances.

The names and symbols of four noble gases are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr).

Noble gases are sometimes called inert gases, and they are the elements in Group 18 of the periodic table. They comprise the elements helium, neon, argon, krypton, xenon, and radioactive radon, which has no known stable isotopes.

Name of a mom-metal which is a liquid = Bromine (Symbol Br)

Name of the three non-metals which are Gases = Hydrogen (Symbol H), Nitrogen (Symbol N), Oxygen (Symbol O)

Name of the three non-metals which are solid = Carbon(Symbol C), Sulphur(Symbol S), Phosphorus(Symbol P), Iodine(Symbol I).

A non metal is a material which do not have properties of metals like lustre. They are non malleable, non ductile, non sonorous and bad conductor of heat and electricity. Example- Carbon, Sulphur,

Metals are materials that are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity. Examples of metals are iron, copper, aluminium, calcium, magnesium, etc.

The elements of groups 1, 2 and 13 to 17 are called normal elements. These elements have their outermost shell incomplete and are highly reactive. Example: Fluorine (F), Chlorine (Cl) etc.
The elements that give out harmful radiations are called Radioactive Elements. Example: Uranium (U), Potassium (K), etc

The discovery of the 118 chemical elements known to exist so far. Among the discovered elements there are 92 metals at present.

An element is a pure substance that cannot be broken down by any physical or chemical means into simpler substances.