Calcium $(C a)$ has atomic number $20$ and mass number $40$ . Which of the following statements is not correct about $C a$ atom?

The number of protons is same as the number of neutrons.

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The number of electrons is same as the number of neutrons.

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The number of protons is half the number of neutrons.

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The number of nucleons is double the number of neutrons.

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Solution

The correct option is D The number of protons is half the number of neutrons.
Number of Protons = atomic number = 20.
Therefore, number of protons = 20.
Number of electrons = number of protons = 20.
Number of neutrons = Mass number - number of protons = 40-20 = 20.
The only option states wrong about $C a$ is C.

Hence, the correct option is C.

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Similar questions

Q. Any chemical element (X) can be represented as

_{Z} X^{A}

where ‘Z’ is the atomic number and ‘A’ is the mass number. The atomic number refers to the number of protons and the mass number refers to the sum of protons and neutrons in an atom. For an element, calcium which has 20 protons and 20 neutrons, identify the correct representation:

Which of the following statements is/ are correct about neutral elements?

(i) Atomic number = number of protons = number of electrons
(ii) Mass number = number of protons + number of neutrons
(iii) Atomic number = number of protons + number of electrons
(iv) Mass number = number of neutrons = number of electrons

Q. Identify the correct statements.
(i) Atomic number = number of protons + number of electrons
(ii) Mass number = number of protons + number of neutrons
(iii) Atomic mass = number of protons = number of neutrons
(iv) Atomic number = number of protons = number of electrons

Q. Which of the following are true for an element?
(i) Atomic number = number of protons + number of electrons
(ii) Mass number = number of protons + number of neutrons
(iii) Atomic mass = number of protons = number of neutrons
(iv) Atomic number = number of protons = number of electrons

Q. Which of the following statement is always correct?

(a) an atom has equal number of electrons and protons

(b) an atom has equal number of electrons and neutrons

(d) an atom has equal number of electrons, protons and neutrons

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Calcium (Ca) has atomic number 20 and mass number 40. Which of the following statements is not correct about Ca atom?

Calcium $(C a)$ has atomic number $20$ and mass number $40$ . Which of the following statements is not correct about $C a$ atom?