Advertisements
Advertisements
प्रश्न
Define: Atomic number
Advertisements
उत्तर
Atomic number— Atomic number refers to the number of protons present in an atom. It is denoted by Z.
APPEARS IN
संबंधित प्रश्न
Write down the name of a compound represented by the following formula:
KNO3
Write down the name of a compound represented by the following formula:
CaCO3
Give the name of the element present in the following compound:
Quick lime
Calculate the number of molecules of sulphur (S8) present in 16 g of solid sulphur.
Define: Atomic weight :
What is the atomicity of the following ?
- Oxygen
- Ozone
- Neon
- Sulphur
- Phosphorus
- Sodium
In what form does oxygen gas occur in nature ?
One of the forms of a naturally occurring solid compound P is usually used for making the floors of houses. On adding a few drops of dilute hydrochloric acid to P, brisk effervescence are produced. When 50 g of reactant P was heated strongly, than 22 g of a gas Q and 28 g of a solid R were produced as products. Gas Q is the same which produced brisk effervescence on adding dilute HCl to P. Gas Q is said to cause global warming whereas solid R is used for white-washing.
- What is (i) solid P (ii) gas Q, and (iii) solid R.
- What is the total mass of Q and R obtained from 50 g of P ?
- How does the total mass of Q and R formed compare with the mass of P taken ?
- What conclusion do you get from the comparison of masses of products and reactant ?
- Which law of chemical combination is illustrated by the example given in this problem ?
Work out the formula for magnesium hydrogencarbonate.
An element X forms the following compounds with hydrogen, carbon and oxygen :
H2X, CX2, XO2, XO3
State the three valencies of element X which are illustrated by these compounds.
Correct the following statement:
A molecule of sulphur is monoatomic.
Why are the symbols and formulae of substances important?
Explain the term – molecules. Give three examples of atoms of the same element forming a molecule. State the atomicity of the same.
Give one example of a polyatomic molecule.
State the main points of the contradiction of Dalton’s atomic theory by the Modern Atomic Theory.
Give a reason why –
Helium is considered monoatomic, but hydrogen a diatomic molecule.
Give a reason why –
Ozone is considered triatomic, but phosphorus a tetratomic molecule.
State the atomicity of the following:
Neon
State the atomicity of the following:
Argon
Which of the following is a short and scientific way of representing one molecule of an element or compound?
Classify the following molecules as the molecules of element or compound
| 1. |  |
|
| 2. |  |
|
| 3. |  |
|
| 4. |  |
The Atomicity of phosphorous is ______
Two elements sometimes can form more than one compound.
Define: Atomicity.
Which of the following contains maximum number of molecules?
Write any two classifications of a molecule.
