Arrange F, N, Be in increasing order of atomic number.
ii)
Where are isobars placed in the modern periodic table and why?
iii) An element has atomic number 16. Is it metal or non-metal, why?
Why do we classify elements ?
Write the formula of the product formed when element ‘A’ with atomic number 11 combine
with element 'B' (9). What is nature of bond formed ?
ATMO III
TYY
Answers
Be, F , N
ii) Isobars are atoms of different elements having the same mass number but different atomic numbers, the number of protons, electrons as well as neutrons are different in all isobars, thus they share no common chemical or physical properties. They are placed in different groups of the modern periodic table as they have different atomic numbers and different properties, the modern periodic table organizes elements on the basis of atomic number and not atomic mass number.
iii) It is a non-metal. If we use the {2,8,8,2} rule for finding out its electronic configuration we get its electronic configuration as {2,8,6}, thus it has more more than four valence electrons, it readily gains two electrons two form an anion and to attain the electronic configuration of the nearest noble gas. So, it is a non-metal.
Elements are classified on the basis of common properties to organize them into groups, this allows the study of one element to find out the properties of all other elements in that group, so it is easier and convenient to classify elements on the basis of common chemical properties.
Element A will have electronic configuration {2,8,1} and element B will have electronic configuration {2,7} . So, the valency of A will be +1 and that of B will be -1 . A is a metal and B is a nonmetal. So, the formula of the product formed will be AB .
The type of bond seen in AB will be electrovalent or ionic.