Isotopes, Isotones and Isobars

Q.

Which of the following is not a radioactive element?

1. Helium

2. Polonium

3. Radium

4. Uranium

Q.

Isotopes are the atoms of different elements with same number of neutrons.

1. True

2. False

Q. What is the number of oxygen atoms present in 126 g of ${HNO}_3$?

1. $36.132\times {10}^{23}$
2. $9.033\times {10}^{23}$
3. $12.044\times {10}^{23}$
4. $16.132\times {10}^{23}$

Q.

The priority order of the following substituent will be:

-OCH₃ ; -N(CH₃)₂ ; -CH₃ ; -H

I II III IV

1. IV>III>II>I

2. I>II>III>IV

3. II>I>III>IV

4. II>III>I>IV

Q. Constituents of nucleus of three atoms A, B and C are given below:
A - 90 protons and 148 neutrons
B - 92 protons and 146 neutrons
C - 90 protons and 146 neutrons
Based on the above data, which of these atoms are isotopes.

1. A and B are isotopes
2. B and C are isotopes
3. A and C are isotopes
4. A, B and C are isotopes

Q. The number of neutrons present in the nucleus of an element X, which is represented as $\begin{array}{c}31\\ 15\end{array}X$ is:

1. 18
2. 13
3. 19
4. 16

Q. How many moles of ammonia weigh 85 g?

1. 5

Q. The number of molecules present in 200 g of baking soda is:

1. $1.43\times {10}^{24}$
2. $2.86\times {10}^{24}$
3. $1.01\times {10}^{28}$
4. $5.05\times {10}^{27}$

Q. Avogadro number is:

1. Number of atoms, one gram of element.
2. Number of molecules present in one gram molecular mass of a substance.
3. Number of molecules present in one gram of substance.
4. All of these.

Q. State the position of cerium (z = 58) and uranium (z = 92) in periodic table?