Advertisements
Advertisements
Question
Helium atom has 2 electrons in its valence shell but its valency is not 2, Explain
Advertisements
Solution
Helium has only one shell (K – shell) and the maximum number of electrons within K shell can be 2. Hence the valency is zero.
APPEARS IN
RELATED QUESTIONS
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.
If the number of electrons in an ion Z3– is 10, the atomic number of element Z will be :
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 is the numerical value of Avogadro number ?
What name is given to the number 6.022 × 1023 ?
What is the number of molecules in 1.5 moles of ammonia ?
If 32 g of sulphur has x atoms, then the number of atoms in 32 g of oxygen will be :
If 12 gram of carbon has x atoms, then the number of atoms in 12 grams of magnesium 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)
How many grams of magnesium will have the same number of atoms as 6 grams of carbon ?
(Mg = 24 u ; C = 12 u )
The mass of one atom of an element X is 2.0 × 10–23 g.
Calculate the atomic mass of element X.
What could element X be ?
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?
An element X has a mass number 4 and atomic number 2. Write the valency of this element?
