Atomic Number

Q.

How many protons, neutrons, and electrons are present in an atom of Aluminum-27?

Q.

Is there any difference between electrons and ß-particles?

Q.

Define the following terms :

(a) Atomic number

(b) Mass number

(c) Nucleons

(d) Valence shell

Q.

How many protons, neutrons, and electrons are in a neutral atom of Sodium?

Q.

In a sample of ethyl ethanoate $\left({\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5\right)$ the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?

1. One of the oxygen atoms has gained electrons

2. One of the oxygen atoms has gained two neutrons

3. The two oxygen atoms are isotopes

4. The two oxygen atoms are isobars.

Q.

Between Cobalt (Co) and Nickel (Ni) which element has

1. Higher atomic mass?
2. Higher atomic number?

Q.

The atomic number of the element calcium is 20. The total number of electrons in calcium is

___

Q.

Why is an Atom Neutral?

Q.

What happens to atomic masses in a chemical reaction where electrons are transferred or shared?

1. Changes according to number of electrons being gained

2. Does not change

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

4. Increases

Q.

Why do ${}_{17}{}^{35}\mathrm{Cl}$ and ${}_{17}{}^{37}\mathrm{Cl}$ have the same chemical properties? In what respect do these atoms differ? What is the fractional mass of chlorine?

Q. Can I get the valency chart of elements?

Q.

Which of the following elements has $17$electrons and $17$protons?

1. Sodium

2. Sulfur

3. Aluminum

4. Chlorine

Q. What is an atom and what is atomic number?

Q.

The atomic number of oxygen and sulfur are $8and16$ respectively. What will be the number of electrons in these?

Q.

If sodium has atomic number 11 and mass number of 23, then the number of protons, neutrons, and electrons in an uncharged atom is :

1. 11, 12, 11

2. 12, 10, 11

3. 11, 13, 11

4. 11, 12, 13

Q.

An ion M^3- contains 10 electrons and 7 neutrons. What is the atomic number and mass number of the element M? Name the element.

Q. Anions are attracted to the_____________

1. walls of the container
2. cathode
3. anode
4. electrolyte

Q.

1 mole of Argon gas contains ______number of fundamental particles.

Q.

What two type quantitative information is conveyed by the symbol $\mathrm{Mg}$

Q.

If an atom A has a mass number 'x' and atomic number 'y' ( $A_y^x$ ) and it forms an ion $A^{-}$ by losing an electron. What can we say about the mass number of the ion?

1. Mass number will be greater than x

2. Mass number will be lesser than x

3. Mass number will be equal to x

4. Mass number varies randomly

Q. The number of electrons in 0.42 g N3 ion is

Q.

Arrange the following in order of their increasing atomic number:

Si, Ne, Mg, S, C

1. C, Ne, Mg, S, Si

2. C, Ne, Mg, Si, S

3. C, Ne, Si, S, Mg

4. S , C, Mg, Si, Ne

Q.

An element is represented as ${}_{20}{}^{40}A$.

(a) What is its atomic number?

(b) What is its mass number?

(c) What is the number of protons in its nucleus?

(d) What is the number of electrons in its atom?

(e) What is the number of neutrons in its nucleus?

(g) What is its valency?

Q.

Identify the atomic number of each of the fol­lowing atoms: Potassium (p$=19$, n$=20$)

Q. _____ number of protons are present in an element X with an atomic number Z and mass number A.

1. A-Z
2. A
3. Z
4. A+Z

Q.

The atomic number of the element calcium is 20. The total number of electrons in calcium is ___

.

Q.

Atomic number is the number of ___ in an atom

1. electrons

2. alpha particles

3. neutrons

4. protons

Q.

What is the atomic number of $\mathrm{Mn}$ ?

Q.

London force increases with increase in molecular weights. (True or False)

1. True

2. False

Q. Atomic weight of boron is $10.81$ and it has two isotopes ${}_5{B}^{10}$ and ${}_5{B}^{11}$. Then ratio of ${}_5{B}^{10}$:${}_5{B}^{11}$ in nature would be:

1. $19:81$
2. $10:11$
3. $15:16$
4. $81:19$