Page 2 - 3.HOME ASSIGNMENT-CONCEPT MAP

Q.7 Identify the correct statements. 1
1.In a compound such as water, the ratio of the mass of hydrogen to the
mass of oxygen is always 8 : 1.
2.If 9 g of water is decomposed, 1 g of hydrogen and 8 g of oxygen are
always obtained.
3.In ammonia, nitrogen and hydrogen are always present in the ratio 3 :
14 by mass.
4.Many compounds are composed of two or more elements and each
such compound has the same elements in the same proportions.
(a) 1 and 3 (b) 1, 2 and 3
(c) 2 and 4 (d) All of these
Concept: Dalton's atomic theory and its drawbacks

Q1. Assertion: Isotopes are the atoms of same element 1
Reason: Isotopes have same mass number
Q2 Assertion: Atoms can neither be created nor be destroyed. 1
Reason: Law of conservation of mass says that matter can neither be
created nor be destroyed.
Q3 Assertion: Atoms of same or different elements combine to form 1
compound atoms.
Reason: Molecules are formed when atoms of same or different
elements combine in a fixed ratio by mass.
Q4 Assertion: The water molecule contains hydrogen and oxygen 1
combined together in the ratio 1:8 by mass irrespective of its source.
Reason: Mass can neither be created nor be destroyed.
Q5 According to Dalton which of the following is correct? 1
a) Atoms can be created
b) Atoms are indivisible
c) Atoms of different elements can be alike.
d) Atoms of same elements can be different.
Q6 Isobars are the atoms of ____________ elements 1

Q7 Atoms can be further divided into sub atomic particles. (True/False) 1

Concept: Symbols of elements

Q1. Latin name for gold is 1
(a) aurum (b) kalium
(c) natrium (d) ferrum
Q2 Wolfram is the Latin name of which of the following element? 1
a) Water
b) Sodium
c) Tungsten
d) Antimony
Q3 What is the Latin name of Mercury? 1
a) Aurum
b) Stibium
c) Hydragyrum
d) Kalium
Q4 Assertion: One atom of Sodium can be represented as Na 1
Reason: The symbol of an element represents one atom of it.