Matter can be divided into mixtures and -------------
Pure substances
How many elements have been discovered till date?
118
Compounds and elements are pure substance. TRUE/FALSE
True
The first letter of an element always written in ----------- letter
Capital
The metal which is liquid at Room temperature is
Mercury
When an atom combines with another atom, it forms a ________
Molecule
Based on chemical properties elements can be categorized into three. Name the three categories.
Metals, Non-metals and Metalloids
A compound containing one atom of carbon and two atoms of oxygen is
CO 2-Carbon dioxide
Write the symbols for the following elements and classify them as solid, liquid and gas Aluminum, carbon, chlorine, mercury, hydrogen and helium
Aluminium and Carbon-Solid
Mercury-Liquid
Chlorine, hydrogen and helium-Gas
Non metal conducting electricity:______:: Metal conducting electricity: Copper
Graphite
A molecule containing three atoms is called a
Triatomic molecule.
Give any two differences between metals and nonmetals with examples.
Metals are lustrous. They have a shiny surface. Metals are generally hard. Most metals are bendable. Most metals are good conductors of electricity. Most metals are good conductors of heat. Most metals are making ringing sound when struck. Gold,Silver
Non-metals are generally soft, Non-metals are non bendable, Non-metals are non ductile ,Non-metals are bad conductors of electricity, Non-metals are bad conductors of heat, Non-metals does not make any sound when they struck. Eg: Bromine, Sulphur.
Write the chemical formula and name the elements present in the following compounds:
a. Sodium chloride b. Potassium hydroxide c. Carbon-di-oxide
NaCl- Sodium and chlorine
KOH-Potassium, Oxygen and Hydrogen
CO2-Carbon,Oxygen
Give the chemical formula for the following elements
a. Hydrogen c. Ozone b. Nitrogen d. Sulphur
H2,O3,N2,S8
Mercury: liquid at room temperature:: Oxygen:__________
Gas at room temperature.
Differentiate between elements and compounds.
Elements contain atoms of same types.
Compounds contains atoms of different types in fixed proportion.
Oxygen, hydrogen, and sulphur are examples of
Non-metals
1. What are compounds? Give two examples.
A compound is a pure substance that is formed when the atoms of two or more elements combine chemically in definite proportions. H2O, NaCl
Calculate the atomicity of H2SO4.
7
Define the following terms with an example of each:
Metal
Non-metal
Metalloid
Metal
Non-metal
Metalloid
Give an example for an element and a compound.
Ozone,CO2
What are elements? What are they made of? Give two examples
Pure substances, made of same type of atoms. Eg Aluminium
Classify the following as elements and compounds. Water, common salt, sugar, carbon dioxide, iodine and lithium
Water, common salt, carbon dioxide-Compounds
sugar iodine and lithium- Elements
Give an example for the elements derived from their Latin names
the symbol for gold is Au after its Latin name Aurum. Similarly, the symbols for copper is Cu after its Latin name Cuprum.
Define the following terms with an example of each:
a. Element b. Compound