Isobars and Isotopes

Q. Give the names of the elements and number of atoms of those elements, present in the following compound
a) Sodium sulphate

Q.

Calculate the number of molecules in 2.5 moles of water.

Q. Atoms with same mass numbers but different atomic number are called .

1. isotopes
2. isomers
3. isobars

Q. The atomic number of calcium and argon are $20$ and $18$ respectively, but the mass number of both these elements is $40$. Such pair is called:

1. Isotopes
2. Isomers
3. Isobars
4. Isotones

Q.

In isobars both chemical and physical property is different and in isotopes only chemical property is different why explain

Q. What are isotones? Gives some examples.

Q.

Which among the following statements about hydrogen is correct?

1. Hydrogen has three isotopes of which protium is the most common

2. Hydrogen ion H⁺, exsits freely in solution

3. Dihydrogen does not act as reducing agent

4. Hydrogen never acts as cation ion

Q.

Which of the following are isotones with each other?

1. 

2. 

3. 

4. 

Q. Identify the correct pair of isobars.

1. ${}_6$C${}^{12}$, ${}_6$C${}^{13}$
2. ${}_{11}$Na${}^{24}$, ${}_{12}$Mg${}^{24}$
3. ${}_8$O${}^{16}$, ${}_8$O${}^{17}$
4. ${}_6$C${}^{14}$, ${}_7$N${}^{14}$

Q. Which pair of succesive elements follow increasing order of atomic weight in mendeleev's periodic table?

1. Calcium and potassium
2. Nitrogen and carbon
3. Lithium and beryllium
4. Nickel and cobalt

Q. Isobars are atoms having same number of__________

1. neutrons
2. protons + neutrons
3. protons
4. electrons

Q. Three elements X, Y and Z form a Dobereiner triad. The atomic weights of X and Z is in the ratio 5 :17. If the sum of the atomic weights of extreme elements is 176, then find the atomic weights of Y.

1. 80
2. 90
3. 88
4. 60

Q.

Atomic numbers of two elements are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements? Define these.

Q.

Statement I: ${}^{20}Ne$ and ${}^{22}Ne$ are isotopes.
Statement II: Noble gases do not exist as isotopes as they are inert.

1. Both statements are true

2. Both statements are false

3. Only Statement I is true

4. Only Statement II is false

Q.

Which of the following are isobars?

${}_{18}^{40}Ar$ ${}_6^{14}C$ ${}_{20}^{40}Ca$ ${}_7^{14}N$

1. None of these

2. [I, IV] and [II, III]

3. [I, III] and [II, IV]

4. [I, II] and [III, IV]

Q. The isotopes of an element X are ${}_z{X}^A,{}_z{X}^{A+1},{}_z{X}^{A+2}$ respectively. What is the ratio of the number of nucleons in these respective isotopes?

1. (A - Z) : ((A + 1) - Z) : ((A + 2) - Z)
2. 1 : 2 : 3
3. 1 : 1 : 1
4. A : (A + 1) : (A + 2)

Q. What is meant by ”atomic number of an element''?​

Q. How many groups and periods were there in Mendeleev’s periodic table?

Q. What are the limitations of Mendeleev’s Periodic table?

Q. Which of the following pair is isodiapheres?

1. 
2. 
3. 
4. 

Q. Which of the following is not isoelectronic?

1. $S^{2-}$
2. $N{a}^{+}$
3. $C{a}^{2+}$
4. $C{l}^{-}$

Q. Statement 1: The mass of middle element was roughly the average of atomic masses of other two elements in the triad.
Statement 2 : Elements in a triad show similar properties.

1. Both statement 1 and statement 2 are wrong.
2. Both statement 1 and statement 2 are correct.
3. Only statement 1 is correct.
4. Only statement 2 is correct.

Q. State True or False
The smallest particle of an element is molecule.

1. True
2. False

Q.

$H_1^1$, $H_1^2$, and $H_1^3$ are examples of isobars.

1. False

2. True

Q. (a) What are the following groups known as?​

(i) Group 1​

(ii) Group 17​

(iii) Group 18​

(b) Name two elements of each group.​

Q.

The isotopes of an element X are ${}_z{X}^A,{}_z{X}^{A+1},{}_z{X}^{A+2}$ respectively. What is the ratio of the number of nucleons in these respective isotopes?

1. 1 : 1 : 1

2. 1 : 2 : 3

3. A : (A + 1) : (A + 2)

4. (A - Z) : ((A + 1) - Z) : ((A + 2) - Z)

Q. Which of the following is not related as isotones with others?

1. ${}_{15}^{31}P$
2. ${}_{17}^{35}Cl$
3. ${}_{16}^{32}S$
4. ${}_{14}^{30}Si$

Q. Isobars are atoms having same number of__________

1. neutrons
2. protons
3. protons + neutrons
4. electrons

Q. Choose the incorrect statement with respect to elements belonging to group 13 to 18.

1. Bromine belongs to halogen family.
2. Nitrogen has 5 electrons in its valence shell.
3. Sulphur and carbon belongs to the same group.
4. Neon is stable in nature.

Q. Difference between isotopes and isobars