Chemistry
This question refers to elements of the periodic table with atomic numbers from 3 to 18. In the table below, some elements are shown by letters, even though the letters are not the usual symbols of the elements.
| 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| A | B | C | D | E | F | G | H |
| 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 |
| I | J | K | L | M | N | O | P |
(a) Which of these is
(i) a noble gas
(ii) a halogen
(iii) an alkali metal
(iv) an element with valency 4
(b) If A combines with F, what would be the formula of the resulting compound?
(c) What is the electronic configuration of G?
Answer
(a) (i) H and P are noble gases, as they are in group zero and have their octet complete.
(ii) G and O are halogens, as they are in group VIIA and have 7 valence electrons.
(iii) A and I are alkali metals, as they are in group IA and have 1 valence electron.
(iv) D and L have valency 4, as they are in group IVA and have 4 valence electrons.
(b) Valency of A [2, 1] is +1, so it tries to donate an electron and attain a stable state.
Valency of F [2, 6] is -2, so it tries to gain two electrons and attain a stable state. Hence, one F atom takes electron from two A atoms. Therefore, the formula of their compound will be A2F
(c) Electronic configuration of G is [2, 7] as its atomic number is 9.
Related Questions
What happens to number of valence electrons in atoms of elements as we go down a group of the periodic table?
Sodium and aluminium have atomic numbers 11 and 13, respectively. They are separated by one element in the periodic table and have valencies 1 and 3 respectively. Chlorine and potassium are also separated by one element in the periodic table (their atomic numbers being 17 and 19, respectively) and yet both have valency 1. Explain.
The position of elements A, B, C, D and E in the periodic table are shown below:
Group 1 Group 2 Group 17 Group 18 – – – D – B C – A – – E (a) State which are metals, non-metals and noble gas in this table.
(b) State which is the most reactive (i) metal (ii) non-metal.
(c) Which type of ion will be formed by element A, B and C.
(d) Which is larger in size (i) D or E (ii) B or C.
Write the electronic configuration of the element 3517T.
(a) What is the group number of T?
(b) What is the period number of T?
(c) How many valence electrons are there in an atom of T?
(d) What is the valency of T?
(e) Is it a metal or a non-metal?
(f) State number of protons and neutrons in T.