Advertisements
Advertisements
Question
Define: Atomic number
Advertisements
Solution
Atomic number : Number of protons present in the nucleus of an atom.
APPEARS IN
RELATED QUESTIONS
Give the name of the element present in the following compound:
Quick lime
Give the name of the element present in the following compound:
Hydrogen bromide
State the term.
The number of atoms present in a molecule of an element _________
Define: Atomic number
Define: Mass number :
What is the atomicity of the following ?
- Oxygen
- Ozone
- Neon
- Sulphur
- Phosphorus
- Sodium
Write the formulae of the following compounds. Also name the elements present in them.
- Water
- Ammonia
- Methane
- Sulphur dioxide
- Ethanol
In what form does oxygen gas occur in nature ?
In what form do noble gases 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.
Calculate the mass of 3.011 × 1024 atoms of carbon.
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.
State the main points of the contradiction of Dalton’s atomic theory by the Modern Atomic Theory.
State the atomicity of the following:
Neon
State the atomicity of the following:
Chlorine
Which of the following is a short and scientific way of representing one molecule of an element or compound?
State true of false. If false, give the correct statement.
NaCl represents one molecule of sodium chloride.
Classify the following molecules as the molecules of element or compound
| 1. |  |
|
| 2. |  |
|
| 3. |  |
|
| 4. |  |
Define: Atomicity.
Derive the relationship between Relative molecular mass and Vapour density.
Which of the following contains maximum number of molecules?
