Atomic Number and Mass Number

Q.

What are isodiaphers? Explain with an example

Q. Suppose the elements X and Y combine to form two compounds $X{Y}_2$ and $X_3{Y}_2$. When 0.1 mole of $X{Y}_2$ weighs 10 g and 0.05 mole of $X_3{Y}_2$ weighs 9 g, the atomic weights of X and Y are

1. 20, 30
2. 30, 20
3. 40, 30
4. 60, 40

Q. Which of the following pairs of compounds is both isoelectronic and isotopic?

1. ${}_{20}^{40}C{a}^{2-},{}_{18}^{40}Ar$
2. ${}_{19}^{39}{K}^{+},{}_{19}^{40}{K}^{+}$
3. ${}_{12}^{24}M{g}^{2+},{}_{12}^{25}Mg$
4. ${}_{11}^{23}Na,{}_{11}^{24}N{a}^{+}$

Q.

An atom has mass number A and atomic number Z.

How many neutrons are present in its nucleus?

Q.

An atom has mass number 209 and atomic number 82. The number of electrons in it is

1. 82

2. 209

3. 127

4. 129

Q. An element is represented by ${}_Z{X}^A$, where Z is atomic number which is also equal to number of proton, A is mass number and X is symbol of the element.
Mass number (A) = Number of protons (Z) + Number of neutrons.
Isotopes: Atoms having same number of proton
Isobar: Elements having same mass number
Isotones: Elements having same number of neutron (A-Z)

An isotone of ${}_{40}^{90}Zr$ is _________.

1. ${}_{36}^{86}Kr$
2. ${}_{19}^{39}K$
3. ${}_{35}^{80}Br$
4. ${}_{50}^{119}Sn$

Q. The atomic number and the mass number of an element M are 25 and 52 respectively.
The number of electrons, protons and neutrons in $M^{2+}$ ion respectively are:

1. 25, 25 and 27
2. 25, 27 and 25
3. 27, 25 and 27
4. 23, 25 and 27

Q. The increasing order for the magnitude of $e/m$ (charge/mass) for an electron (e), a proton (p) and a neutron (n) respectively is:

1. $e<p<n$
2. $n<p<e$
3. $n<e<p$
4. $p<e<n$

Q.

Which is the correct statement about proton?

1. Proton is nucleus of deuterium

2. Proton is ionized hydrogen molecule

3. Proton is ionized hydrogen atom

4. Proton is $\alpha$-particle

Q. The number of protons, neutrons and electrons in ${}_{89}^{231}Y$ are:

1. 89, 89, 242
2. 89. 142, 89
3. 89, 71, 89
4. 89, 231, 89

Q.

Draw the geometric atomic structure of ${}_{19}{}^{39}\mathrm{K}$ , showing clearly the number of neutrons, number of protons and number of electrons.

Q. An element has an atomic number of $11$ and mass number of $24$. Then nucleus consists of:

1. $11$ protons, $13$ neutrons
2. $13$ protons, $11$ neutrons
3. $11$ protons, $13$ neutrons, $13$ electrons
4. $13$ protons, $11$ electrons

Q. An element is represented by ${}_Z{X}^A$, where Z is atomic number which is also equal to number of proton, A is mass number and X is symbol of the element.
Mass number (A) = Number of protons (Z) + Number of neutrons.
Isotopes: Atoms having same number of proton
Isobar: Elements having same mass number
Isotones: Elements having same number of neutron (A-Z)

The sum of the number of electrons, protons and neutrons in the three isotopes ${(}^{16}O{,}^{17}O{,}^{18}O)$ of oxygen is:

1. 36
2. 57
3. 75
4. 68

Q. The relative charges on an electron, a proton and a neutron respectively are:

1. $+1,+1,0$
2. $-1,+1,0$
3. $-1,0,+1$
4. $0,+1,-1$

Q. Arrange the elements in increasing order of their atomic mass

1. Nitrogen
2. Hydrogen
3. Oxygen
4. Carbon

Q. Which of the following pair(s) is/are isodiaphers?

1. ${}_6^{14}Cand{}_{11}^{23}Na$
2. ${}_{12}^{24}Mgand{}_{11}^{23}Na$
3. ${}_2^{4}Heand{}_8^{15}O$
4. ${}_9^{19}Fand{}_6^{13}C$

Q. Any neutral atom (atomic number > 1) has:

1. Electrons and protons
2. Neutrons, electrons and protons
3. Neutrons and electrons
4. Neutrons and protons

Q. An isotone of $G{e}_{32}^{76}$ is:

1. $G{e}_{32}^{77}$
2. $A{s}_{33}^{76}$
3. $S{e}_{34}^{77}$
4. $S{e}_{34}^{78}$

Q. The number of electrons and neutrons in an element are 18 and 20 respectively. Its mass number is

1. 2
2. 37
3. 17
4. 38

Q. The number of protons, neutrons and electrons in ${}_{89}^{231}Y$ are:

1. 89, 89, 242
2. 89. 142, 89
3. 89, 71, 89
4. 89, 231, 89

Q. An alpha particle is:

1. Identical to a helium nucleus
2. Ionized hydrogen atom
3. Helium atom
4. Hydrogen atom

Q. Assuming ideal gas behaviour, the ratio of density of ammonia to that of hydrogen chloride at same temperature and pressure is: (Atomic wt. of $Cl$ 35.5 u)

<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> JEE (MAIN)- 2018

1. 0.64
2. 1.64
3. 1.46
4. 0.46

Q. A hypothetical sub-atomic particle has a mass of one-third of an electron and a charge that is double of a proton. Calculate the charge to mass ratio of the particle.

1. $1.05\times {10}^{-12}{\text{C kg}}^{-1}$
2. $1.05\times {10}^{12}{\text{C kg}}^{-1}$
3. $8.36\times {10}^{21}{\text{C kg}}^{-1}$
4. $1.05\times {10}^{-21}{\text{C kg}}^{-1}$

Q. $B{e}^{2+}$ is isoelectronic with which of the following ions?

1. $H^{+}$
2. $L{i}^{+}$
3. $N{a}^{+}$
4. $M{g}^{2+}$

Q. $B{e}^{2+}$ is isoelectronic with which of the following ions?

1. $H^{+}$
2. $L{i}^{+}$
3. $N{a}^{+}$
4. $M{g}^{2+}$

Q. The number of neutrons in dipositive zinc ion with mass number 70 is:

1. 34
2. 36
3. 38
4. 40

Q. A solution containing $1.8\text{g}$ of a non-electrolyte (empirical formula $C{H}_{2}O$) in $40\text{g}$ of water is observed to freeze at $-0.465{}^{\circ }\text{C}$. The molecular formula of the compound is:
($K_f$ of water $=1.86{\text{kg K mol}}^{-1})$

1. $C_3{H}_6{O}_3$
   
2. $C_4{H}_8{O}_4$
   
3. $C_6{H}_{12}{O}_6$
   
4. $C_2{H}_4{O}_2$
   

Q. A compound $M_p{X}_q$ has cubic close packing (ccp) arrangement of X. Its unit cell structure is shown below. The empirical formula of the compound is

1. MX
2. $M{X}_2$
3. $M_{2}X$
4. $M_5{X}_{14}$

Q. Isodiapheres are the atoms of two elements having same value of:

1. $\frac{p}{n}$
2. ($p-n)$
3. ($n-p)$
4. ($n\times p)$

Q. Match the properties of the species in Column I with the calculated number in Column II.
$\begin{array}{cccc}& \text{Column I}& & \text{Column II}\\ i.& \text{Number of protons in the element with mass number 81}& p.& 50\\ & \text{and having}31.7\%\text{more neutrons than protons}& & \\ ii.& \text{Ionic mass of}{M}^{2+}\text{which is isoelectronic of}C{O}_2\text{and has}& q.& 26\\ & \text{(Z+2) neutrons}.& & \\ iii.& \text{Ionic mass of}{X}^{-}\text{with 17 protons and having}11.1\%& r.& 35\\ & \text{more neutrons than electrons}& & \\ iv.& \text{Atomic number of}{M}^{3+}\text{with mass number 56 and having}& s.& 37\\ & 30.4\%\text{more neutrons than electrons}& & \end{array}$

1. $\begin{array}{cc}iii& iv\\ p& q\end{array}$
2. $\begin{array}{cc}i& ii\\ q& p\end{array}$
3. $\begin{array}{cc}iii& iv\\ s& q\end{array}$
4. $\begin{array}{ccc}i& ii& \\ r& q& \end{array}$