Chemistry
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].
An element 'Y' has electronic configuration 2, 8, 6. The element 'Y' is a …………… [metal/non-metal/noble gas].
A …………… [proton/neutron] is a sub-atomic particle with no charge and unit mass.
An element Z with zero valency is a …………… [metal/noble gas/non-metal].
Magnesium atom with electronic configuration 2, 8, 2 achieves stable electronic configuration by losing two electrons, thereby achieving stable electronic configuration of the nearest noble gas …………… [neon/argon].
Answer
An element 'X' has six electrons in its outer or valence shell. Its valency is -2.
An element 'Y' has electronic configuration 2, 8, 6. The element 'Y' is a non-metal.
A neutron is a sub-atomic particle with no charge and unit mass.
An element Z with zero valency is a noble gas.
Magnesium atom with electronic configuration 2, 8, 2 achieves stable electronic configuration by losing two electrons, thereby achieving stable electronic configuration of the nearest noble gas neon.
Related Questions
With reference to formation of compounds from atoms by electron transfer - electrovalency, state the basic steps in the conversion of sodium & chlorine atoms to sodium & chloride ions leading to the formation of the compound - sodium chloride.
[electronic configuration of: Na = 2,8,1 & Cl = 2,8,7]
Match the statements in List I with the correct answer from List II.
List I List II 1. Mass number of an atom is the number of protons and A: Electron 2. The sub-atomic particle with a negligible mass. B: Argon 3. An atom having stable electronic configuration. C: Nitrogen 4. A molecule formed by sharing of electrons [covalency]. D: Sodium 5. A metallic atom having unstable electronic configuration. E: Neutrons The diagram represents an isotope of hydrogen [H]. Answer the following:
![The diagram represents an isotope of hydrogen [H]. Are isotopes atoms of the same element or different elements. Do isotopes have the same atomic number or the same mass number. Atomic Structure, Simplified Chemistry Dalal Solutions ICSE Class 8.](https://cdn1.knowledgeboat.com/img/scd8/hydrogen-isotope-simplified-chemistry-icse-class-8-151x212.png)
Are isotopes atoms of the same element or different elements.
Do isotopes have the same atomic number or the same mass number.
If an isotope of 'H' has mass no. = 2, how many electrons does it have.
If an isotope of 'H' has mass no. = 3, how many neutrons does it have.
Which sub-atomic particles in the 3 isotopes of 'H' are the same.
State the electronic configuration for each of the following:
Hydrogen [p = 1].
Boron [p = 5]
Nitrogen [p = 7].
Neon [p = 10]
Magnesium [p = 12].
Aluminium [p = 13].
Sulphur [p = 16].
Argon [p = 18].
Potassium [p = 19].
Calcium [p = 20].