Mass Number and Representation of Atom

Q.

An atom of sodium has an atomic number of 11 and a mass number of 23. Which of the following statements is correct?

1. An atom of sodium has 11 protons, 11 electrons, and 11 neutrons.

2. An atom of sodium has 11 protons, 12 electrons, and 11 neutrons.

3. An atom of sodium has 11 protons, 11 electrons, and 12 neutrons.

4. An atom of sodium has 11 protons, 12 electrons, and 12 neutrons

Q. Question 3
The number of electrons in an element X is 15 and the number of neutrons is 16. Which of the following is the correct representation of the element?

(a) ${}_{15}^{31}X$
(b) ${}_{16}^{31}X$
(c) ${}_{15}^{16}X$
(d) ${}_{16}^{15}X$

Q.

The atomic number and mass number of sodium are 11 and 23 respectively. What information is conveyed by this statement?

Q.

The atomic mass of hydrogen atom is ________.

Q.

The composition of the nuclei of two atomic species $\mathrm{X}$ and $\mathrm{Y}$ are given as under $\mathrm{Protons}=6\left(\mathrm{X}\right):6\left(\mathrm{Y}\right)$, $\mathrm{Neutrons}=6\left(\mathrm{X}\right):8\left(\mathrm{Y}\right)$. Give the mass numbers of $\mathrm{X}$ and $\mathrm{Y}$. What is the relation between the two species?

Q.

If an atom of an element contains 17 electrons and 18 neutrons, find the number of protons, atomic number and mass number of the element.

Q.

The atom of an element is made up of 4 protons, 5 neutrons and 4 electrons. What are its atomic number and mass number ?

Q.

What are the difference between particles and atoms?

Q.

What are atoms made up of ?

Q.

Define isobars.

Q.

The positively charged atom is known as a _______

Q.

Can we see an electron?

Q.

Why do all elements have fractional atomic mass?

Q.

Complete the following table relating to the atomic structure of some elements.

$\begin{array}{cccccc}\text{Element}& \text{Atomic}& \text{Mass}& \text{Number of}& \text{Number of}& \text{Number of}\\ \text{Symbol}& \text{Number}& \text{Number}& \text{Neutrons}& \text{Electrons}& \text{Protons}\\ Li& 3& 6& & & \\ Cl& 17& & 20& & \\ Na& & & 12& & 11\\ Al& & 27& & & 13\\ S& & 32& 16& & \end{array}$

Q.

Neon occurs as two isotopes of mass numbers 20 and 22. Its relative atomic mass is 20.2. What is the percentage of ²⁰Ne in naturally occurring neon?

1. 90

2. 80

3. 20

4. 10

Q. Question 10
Identify the $M{g}^{2+}$ ion from the figure where, n and p represent the number of neutrons and protons respectively.

Q.

The number of electrons in the atom of an element X is 15 and the number of neutrons is 16. Which of the following is the correct representation of an atom of this element?

1. ${}_{15}^{31}\text{X}$

2. ${}_{16}^{31}\text{X}$
   

3. ${}_{16}^{15}\text{X}$

4. ${}_{15}^{16}\text{X}$
   

Q.

Name the following :

A triatomic molecule

Q. What is the mass number of aluminium if it has 13 protons and 14 neutrons?

1. 13
2. 14
3. 28
4. 27

Q.

An alpha-particle has how many neutrons?

Q.

The first ionization energy of the d-block elements are________.

Q.

Give the relationship between atomic number and mass number.

Q. 1.What are neucleons ?
2. What is the atomicity of Ca(OH)₂?

Q.

The composition of two atomic particles is given below :

$\begin{array}{ccc}& & \\ X& Y& \\ \text{Protons}:& 8& 8\\ \text{Neutrons}:& 8& 9\\ \text{Electrons}:& 8& 8\end{array}$

(i) What is the mass number of X ?

(ii) What is the mass number of Y ?

(iii) What is the relation between X and Y ?

(iv) which element/elements do they represent?

Q.

Draw the orbital diagram of ${}_{20}{}^{40}\mathrm{Ca}^{+2}$ ion and state the number of three fundamental particles present in it.

Q. Complete the following table.​

(i)

Atomic number​	Mass number​	Number of neutrons​	Number of protons​	Number of electrons​	Name of the Atomic species​
9​	-​	10​	-​	-​	-​

(ii)

Atomic number​	Mass number​	Number of neutrons​	Number of protons​	Number of electrons​	Name of the Atomic species​
16​	32​	-​	-​	-​	Sulphur​

(iii)

Atomic number​	Mass number​	Number of neutrons​	Number of protons​	Number of electrons​	Name of the Atomic species​
16​	32​	-​	-​	-​	Sulphur​

(iv)

Atomic number​	Mass number​	Number of neutrons​	Number of protons​	Number of electrons​	Name of the Atomic species​
-​	2​	-​	1​	-​	-​

(v)

Atomic number​	Mass number​	Number of neutrons​	Number of protons​	Number of electrons​	Name of the Atomic species​
-​	1​	0​	1​	1​	-​

Q.

Define atomicity of a gas.

Q.

Name the following.

A subatomic particle that carries a negative charge.

Q. The distribution of electrons In K, L, M, N shells and the number of neutrons in the nuclei of the following elements are given below:
$$\begin{array}{cccccc}\text{Elements}& \text{K}& \text{L}& \text{M}& \text{N}& \text{No. of Neutrons}\\ \text{A}& 2& \text{6}& \text{-}& \text{-}& \text{8}\\ \text{B}& 2& \text{8}& \text{2}& \text{-}& \text{1}2\\ \text{C}& 2& \text{8}& \text{5}& \text{-}& \text{1}6\\ \text{D}& 2& \text{8}& \text{8}& \text{-}& \text{2}2\end{array}$$
The mass number of A, B, C, and W respectively is:

1. 40, 24, 16, 31
2. 16, 24, 31, 40
3. 31, 24, 16, 40
4. 31, 40, 16, 24

Q. Do the Mass of electron proton and neutron of every element is same?
means for eg.hydrogen and oxygen atoms have electron proton and neutron in them..so can we say that the mass of electron proton and neutron in hydrogen and oxygen is the same..