Advertisements
Advertisements
प्रश्न
Define ‘formula unit’ of an ionic compound. What is the formula unit of (i) sodium chloride, and
(ii) magnesium chloride ?
Advertisements
उत्तर
Formula unit of an ionic compound refers to the empirical formula of an ionic or covalent molecule. It is the lowest whole number ratio of ions that make up the electrically neutral ionic compound. Formula unit represents the smallest unit of a compound.
The formula unit of sodium chloride is NaCl.
The formula unit of magnesium chloride is MgCl2.
APPEARS IN
संबंधित प्रश्न
Write down the formulae of magnesium hydroxide.
The formula of carbonate of a metal M is M2CO3.
What will be the formula of its phosphate ?
Name the element in the compound and give the formula of the following compound:
Phosphoric acid
Write the formula of the following compound:
Potassium sulphate
Write the formula of the following compound:
Calcium chloride
Write the formula of the following compound:
Calcium bicarbonate
Write the formula of the following compound:
Magnesium sulphate
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
KNO3
Complete the following crossword puzzle (Fig. 3.1) by using the name of the chemical elements. Use the data given in Table.
| Across | Down | ||
| 2 | The element used by Rutherford during his α–scattering experiment | 1 | A white lustrous metal used for making ornaments and which tends to get tarnished black in the presence of moist air |
| 3 | An element which forms rust on exposure to moist air | 4 | Both brass and bronze are alloys of the element |
| 5 | A very reactive non–metal stored under water | 6 | The metal which exists in the liquid state at room temperature |
| 6 | Zinc metal when treated with dilute hydrochloric acid produces a gas of this element which when tested with burning splinter produces a pop sound. | 8 | An element with symbol Pb |
Play a game for writing formula.
Example 2: A low-cost model for writing formulae: Take empty blister packs of medicines. Cut them in groups according to the valency of the element, as shown in the figure. Now, you can make formulae by fixing one type of ion into other.
For example:
The formula for sodium sulphate:
2 sodium ions can be fixed on one sulphate ion.
Hence, the formula will be Na2SO4.
Do it yourself:
Now, write the formula of sodium phosphate.
