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Question
Give a reason why elements are tabulated in a table called the ‘Periodic table’.
Solution
For arranging all the elements in a systematic and simple manner. The arrangement of elements was done in the form of a table called Periodic Table in which elements are arranged in increasing order of their atomic numbers. Elements in the Periodic Table are arranged in Horizontal rows called Periods and vertical columns called groups. Metallic elements are placed on the left non-metallic on the right and noble gases on the extreme right of the Periodic table.
RELATED QUESTIONS
Why is the symbol S for sulphur, but Na for sodium and Si for silicon?
Match the non-metallic elements – with their correct symbols. Non-metallic elements are:
| Non-Metallic elements | Symbol |
| (a) Carbon | (1) O |
| (b) Chlorine | (2) I |
| (c) Oxygen | (3) Si |
| (d) Phosphorus | (4) C |
| (e) Hydrogen | (5) Cl |
| (f) Nitrogen | (6) P |
| (g) Iodine | (7) F |
| (h) Bromine | (8) H |
| (i) Fluorine | (9) S |
| (j) Silicon | (10) Br |
| (k) Sulphur | (11) N |
Match the symbols of – radicals – with their correct combining power or capacity, (valency).
(a) OH
(b) So4
(c) No3
(d) Co3
Combining power or capacity – A : 3; B : 2; C : 1. (negative valencies)
Give the symbol of the following element:
Xenon
State the type of element for the following:
Carbon
State whether the following ion or radical given below of a non-metallic element exhibits valency: 1–, 2– or 3–. (write the ion or radical with the correct valency).
Iodide
State whether the following ion or radical given below of a non-metallic element exhibits valency: 1–, 2– or 3–. (write the ion or radical with the correct valency).
Sulphide
Name three metals whose symbols are derived: from their Latin names.
State why the molecular formula of zinc carbonate is ZnCO3 .
Which of the following symbols of elements are incorrect? Give their correct symbols
- Cobalt CO
- Carbon c
- Aluminium AL
- Helium He
- Sodium So
