Select the correct answer from the choice in bracket to complete each sentence:-
An element 'X' has six electrons in its outer or valence shell. Its valency is _________ [+2/-2/-1].

Select the correct answer from the choice in bracket to complete each sentence:- An element Z with zero valency is a — [metal/noble gas/non-metal].

Select the correct answer from the choice in bracket to complete each sentence:- An element 'Y' has electronic configuration 2, 8, 6. The element 'Y' is a _________ [metal/non-metal/noble gas].

Select the correct answer from the choice in bracket to complete each sentence: An example of a monoatomic molecule is _______ [hydrogen/helium).

An element A has 2 electrons in its, fourth shell. State its valency

Select the correct answer from the choice in bracket to complete each sentence:- A- [proton/neutron] is a sub-atomic particle with no charge and unit mass.

Select the correct answer from the choice in bracket to complete each sentence: The reactive element from the two monoatomic elements is _______ [neon/silicon].

Select the correct answer from the choice in bracket to complete each sentence. Matter is added or removed during a - [chemical/physical] change

Select the correct answer from the choice in bracket to complete each sentence: The gas which has now replaced hydrogen in air balloons is _____________[argon, helium, neon].

Select the correct answer from the choice in bracket to complete each sentence. A change in which a substance retains its identity is a — [physical/chemical] change

Select the correct answer from the choice in bracket to complete each sentence: Dust in air is an example of________ [heterogeneous/homogeneous) mixture.