Advertisements
Advertisements
प्रश्न
An element X has a mass number 4 and atomic number 2. Write the valency of this element?
Advertisements
उत्तर
The element X has its atomic number as 2. Thus, an atom of X contains two electrons in it. These 2 electrons fill the X-shell completely.
Thus the valency of X is zero.
APPEARS IN
संबंधित प्रश्न
An element has an atomic number of 11 and its mass number is 23. What is the arrangement of electrons in the shells? State nuclear composition of an atom of the element.
The number of electrons in an ion Y2+ is 10. The atomic number of element Y is most likely to be :
The atom of an element X contains 17 protons, 17 electrons and 18 neutrons whereas the atom of an element Y contains 11 protons, 11 electrons and 12 neutrons.
- What type of ion will be formed by an atom of element X ? Write the symbol of ion formed.
- What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from X ?
- What type of ion will be formed by an atom of element Y ? Write the symbol of ion formed.
- What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from Y ?
- What is the atomic mass of (i) X, and (ii) Y ?
- What could the elements X and Y be ?
What name is given to the number 6.022 × 1023 ?
What name is given to this number ?
What is the number of molecules in 1.5 moles of ammonia ?
Calculate the number of molecules in 4 g of oxygen.
If 32 g of sulphur has x atoms, then the number of atoms in 32 g of oxygen will be :
What weight of oxygen gas will contain the same number of molecules as 56 g of nitrogen gas ?
(O = 16 u ; N = 14 u)
What mass of nitrogen, N2, will contain the same number of molecules as 1.8 g of water, H2O ?
(Atomic masses : N = 14 u ; H = 1 u ; O = 16 u)
If one gram of sulphur contains x atoms, calculate the number of atoms in one gram of oxygen element.
(Atomic masses : S = 32 u ; O = 16 u)
Which has more number of atoms?
100g of N2 or 100 g of NH3
A silver ornament of mass ‘m’ gram is polished with gold equivalent to 1% of the mass of silver. Compute the ratio of the number of atoms of gold and silver in the ornament.
. A sample of ethane (C2H6) gas has the same mass as 1.5 ×1020 molecules of methane (CH4). How many C2H6 molecules does the sample of gas contain?
In the atom of an element X, 6 electrons are present in the outermost shell. If it acquires noble gas configuration by accepting requisite number of electrons, then what would be the charge on the ion so formed?
Match the names of the Scientists given in column A with their contributions towards the understanding of the atomic structure as given in column B
| (A) | (B) | ||
| (a) | Ernest Rutherford | (i) | Indivisibility of atoms |
| (b) | J.J.Thomson | (ii) | Stationary orbits |
| (c) | Dalton | (iii) | Concept of nucleus |
| (d) | Neils Bohr | (iv) | Discovery of electrons |
| (e) | James Chadwick | (v) | Atomic number |
| (f) | E. Goldstein | (vi) | Neutron |
| (g) | Mosley | (vii) | Canal rays |
The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements?
