$A$ helium atom has two electrons in its valence shell,but its valency is not two. Explain.
(N/A) The valence shell of a helium atom is the $K$-shell,which can hold a maximum of $2$ electrons. Since the $K$-shell is completely filled with $2$ electrons,the atom is stable and does not need to gain,lose,or share electrons to achieve a stable configuration. Therefore,its combining capacity or valency is $0$.
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Similar Questions
Rutherford's $\alpha-$ particle scattering experiment showed that
$(i)$ Electrons have negative charge
$(ii)$ The mass and positive charge of the atom is concentrated in the nucleus
$(iii)$ Neutron exists in the nucleus
$(iv)$ Most of the space in atom is empty
Which of the above statements are correct?
$(i)$ Electrons have negative charge
$(ii)$ The mass and positive charge of the atom is concentrated in the nucleus
$(iii)$ Neutron exists in the nucleus
$(iv)$ Most of the space in atom is empty
Which of the above statements are correct?
Medium
View SolutionAtomic models have been improved over the years. Arrange the following atomic models in their chronological order:
$(i)$ Rutherford's atomic model
$(ii)$ Thomson's atomic model
$(iii)$ Bohr's atomic model
$(i)$ Rutherford's atomic model
$(ii)$ Thomson's atomic model
$(iii)$ Bohr's atomic model
Medium
View Solution$(a)$ Both helium and beryllium have two electrons in their valence shells. Helium is a noble gas whereas beryllium is a metal. Justify.
$(b)$ Hydrogen exists in three isotopic forms. Why are the isotopes of hydrogen chemically alike?
$(b)$ Hydrogen exists in three isotopic forms. Why are the isotopes of hydrogen chemically alike?
Medium
View SolutionRutherford's alpha $(\alpha)$ particles scattering experiment resulted in the discovery of:
Easy
View SolutionState whether the following statement is true or false:
One atomic mass unit is a mass unit equal to exactly one-twelfth $(1/12)$ the mass of one atom of carbon-$12$.
One atomic mass unit is a mass unit equal to exactly one-twelfth $(1/12)$ the mass of one atom of carbon-$12$.
Easy
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