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प्रश्न
Define: Atomic number
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उत्तर
Atomic number : Number of protons present in the nucleus of an atom.
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संबंधित प्रश्न
Write down the name of a compound represented by the following formula:
CaCO3
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: Mass number :
Define: Atomic weight :
What is the atomicity of the following ?
- Oxygen
- Ozone
- Neon
- Sulphur
- Phosphorus
- Sodium
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 ?
Molecular compounds are usually formed by the combination between :
An element A forms an oxide A2O5.
What is the valency of element A ?
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.
Correct the following statement:
A molecule of sulphur is monoatomic.
State the main points of the contradiction of Dalton’s atomic theory by the Modern Atomic Theory.
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:
Oxygen
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.
Which of the following is a triatomic molecule?
If a molecule is made of similar kinds of atoms, then it is called ______ atomic molecule.
The Atomicity of phosphorous is ______
Two elements sometimes can form more than one compound.
Give any two examples for heterodiatomic molecules.
Derive the relationship between Relative molecular mass and Vapour density.
Write any two classifications of a molecule.
