Property which is same for the following species is:

 N^3–, O^2–, F^–, Na⁺, Mg²⁺ and Al³⁺ 

1. Ionic radii

2. Number of electrons

3. Nuclear charge

4. None of the above 

The total number of electrons present in one mole of methane is:

$1.$ $6.023$ $\times$ ${10}^{23}$
$2.$ $6.023$ $\times$ ${10}^{24}$
$3.$ $6.023$ $\times$ ${10}^{22}$
$4.$ $1.619\times$ ${10}^{23}$

The total number and mass of neutrons in 7 mg of ¹⁴C would be :

(Assume that mass of a neutron = 1.675 × 10^–27 kg)

\(1 .\) \(2 . 41\) \(\times\) \(\left(10\right)^{21}\) \(,\) \(4 . 03\) \(\times\) \(\left(10\right)^{– 6}\) \(kg\)
\(2 .\) \(6 . 23\) \(\times\) \(\left(10\right)^{23}\) \(,\) \(1 . 67\) \(\times\) \(\left(10\right)^{- 21} kg\)
\(3 .\) \(1 . 22\) \(\times\) \(\left(10\right)^{22}\) \(,\) \(4 . 03\) \(\times\) \(\left(10\right)^{6}\) \(kg\)
\(4 .  2 . 41\) \(\times\) \(\left(10\right)^{21}\) \(,\) \(4 . 03\) \(\times\) \(\left(10\right)^{- 6}\) \(g\)

An atom of an element contains 29 electrons and 35 neutrons. The number of protons in the element would be:

The charge on the oil drop is –1.282 × 10^–18C. The number of electrons present in it would be :

1. 15

2. 8

3. 2

4. 6

An element with a mass number of 81 contains 31.7% more neutrons as compared to protons. The atomic symbol of the element would be

$1.$ ${}_{35}{}^{81}\mathrm{Br}$
$2.$ ${}_{36}{}^{81}\mathrm{Br}$
$3.$ ${}_{35}{}^{79}\mathrm{Br}$
$4.$ ${}_{36}{}^{79}\mathrm{Br}$

An ion with a mass number of 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. The symbol of the ion is -

$1.$ ${}_{26}{}^{56}\mathrm{Fe}^{+3}$
$2.$ ${}_{26}{}^{57}\mathrm{Fe}^{+3}$
$3.$ ${}_{27}{}^{58}\mathrm{Fe}^{+3}$
$4.$ ${}_{25}{}^{56}\mathrm{Fe}^{+3}$

The mass and charge of one mole of electrons are, respectively:

1. 5.48 × ${10}^{-7}$ kg, 9.65 C, 
2. 5.48 × ${10}^{-7}$ C, 1.098 x 10²⁷
3. 5.48 × ${10}^{-7}$ kg, 9.65 × ${10}^4$ C
4. 9.65 × ${10}^4$ C, 1.098 x 10²⁷

The maximum number of neutrons are present in the nuclei of

$1.$ ${\mathrm{O}}_8^{16}$
$2.$ ${\mathrm{Mg}}_{12}^{24}$
$3.$ ${\mathrm{Fe}}_{26}^{56}$
$4.$ ${\mathrm{Sr}}_{38}^{88}$

The complete symbol for the atom with the given atomic number (Z) and atomic mass (A) would be, respectively,

1.  ${}_4{}^9\mathrm{Be}$   ${}_{92}{}^{233}\mathrm{U}$     ${}_4{}^9\mathrm{Be}$

2.  ${}_{17}{}^{35}\mathrm{Cl}$    ${}_{92}{}^{233}\mathrm{U}$    ${}_4{}^9\mathrm{Be}$

3.  ${}_4{}^9\mathrm{Be}$    ${}_{17}{}^{35}\mathrm{Cl}$     ${}_{92}{}^{233}\mathrm{U}$

4. ${}_{92}{}^{233}\mathrm{U}$    ${}_4{}^9\mathrm{Be}$    ${}_{17}{}^{35}\mathrm{Cl}$