Mass Number and Representation of Atom

Q. An atom of phosphorus has the symbol ${}_{15}^{31}\text{P}$. How many protons, electrons and neutrons are present in an atom of phosphorus?

1. Protons-15, electrons-15, neutron-16
2. Protons-15, electrons-15, neutron-15
3. Protons-15, electrons-16, neutrons-16
4. Protons-16, electrons-16, neutrons-15

Q.

Show the formation of sulphide ion.(Atomic number of sulphur =16)

Q.

Draw the diagrams representing the atomic structures of the following :

(a) Nitrogen

(b) Neon

Q.

A neutral element has 3 electrons, the atomic number of the element is _____.

Q.

A dinegative ion of an element has protons whose mass is equal to 14, 696 times that of an electron. The number of neutrons is more than the number of protons by 2 . What could be the mass number?

1. 16

2. 8

3. 18

4. 10

Q.

How many atoms are present in Calcium biphosphate?

1. 5

2. 6

3. 7

4. 8

Q.

Identify the element given below.

1. Hydrogen
2. Helium
3. Lithium
4. Carbon

Q.

In order to attain octet configuration, the atoms share, lose or gain electrons, then its atomic mass

1. Does not change

2. Changes according to number of electrons being gained

3. Remains the same in case of sharing, but it changes in case of losing or gaining electrons

4. Increases

Q. The formula unit mass of $N{a}_{2}O$ is ____.

1. 52
2. 62
3. 50
4. 48

Q.

What Do You Mean By Social Advertisement

Q.

19. The mass number and atomic number of an element is $23$ and $11$ respectively. What is the number of nucleons present in it?

Q.

Complete the following:
Mercury (+2) ion contains 80 protons, 78 electrons, and 120 nucleons. Its mass number is ________.

Q.

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

Q.

In an experiment, 2 g of nitrogen gas reacts with 6 g of hydrogen to form 8 g of ammonia. When 2 g of nitrogen reacts with 12 g of hydrogen, what mass of ammonia will be produced?

1. 14 gm

2. 10 gm

3. 8 gm

4. 7 gm

Q. The atomic number of phosphorus is 15. Its electronic configuration will be ____, and its valency will be____.

1. 2, 8, 4; 4
2. 2, 8, 5; 1
3. 2, 8, 5; 3
4. 2, 8, 2; 2

Q.

What is lithium?

Q.

In an experiment, 2 g of Nitrogen gas reacts with 6 g of Hydrogen to form 8 g of Ammonia. Then when 2 g of Nitrogen reacts with 12 g of Hydrogen, then what mass of Ammonia will be produced?

1. 10 gm

2. 14 gm

3. 7 gm

4. 8 gm

Q.

An atom has a mass number of $35$ and atomic number $17$. The number of protons are

1. $17$

2. $18$

3. $20$

4. $19$

Q. Atomic mass of element X with 8 electrons and 8 neutrons is.

1. 8
2. 16
3. 24

Q.

Complete the missing links
1 u stands for ________ of a carbon atom.

Q. What is meant by mass number? Explain how the atomic number and mass number of carbon is 6 and 12, respectively.

Q.

What information does the atomic number give?

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

Q.

Which of the following is incorrectly represented?

1. Oxygen- $O_8^{16}$
2. Sodium- $N{a}_{11}^{23}$
3. Fluorine- $F_{10}^{19}$
4. Carbon- $C_{12}^6$

Q.

Write the atomic number and electronic configuration of the following elements.

(i) Sodium

(ii) Chlorine

(iii) Neon

(iv) Magnesium

Q.

Which among the following is the right representation for carbon with its atomic and mass number?

1. ${}_6^{12}C$

2. ${}_{12}^{6}C$

3. ${}_{12}^{12}C$

4. ${}_{11}^{6}C$

Q.

What is meant by the periodicity in properties?

Q.

What happen to the atomic number of an element, when it emits a $\beta -$particle ?

Q.

From the symbol ${}_{40}{}^{20}\mathrm{Ca}$ state:

Atomic number

Q. Silver nitrate solution was mixed with 5g of sodium chloride solutions to verify law of conservation of mass. 8.1g of silver chloride was formed and sodium nitrate formed was equal to half of the amount of silver nitrate solution used what is the amount of silver nitrate used and sodium nitrate formed