Tag: atom

Questions Related to atom

An αα particle is:

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. a hydrogen molecule

  2. a helium nucleus

  3. an electron

  4. a proton

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Correct Option: B
Explanation:

$(B)$ a helium nucleus 


$Reason$ : An $\alpha$ particle is a positively charged particle consists of two protons and two neutrons , all held together by the same strong nuclear force that binds the nucleus of any atom , emitted by some radioactive substances and identical to the nucleus of helium atom . It carry a charge of $+2$. 

What makes the atom of one element different from another element's atom ?

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. Number of protons

  2. Number of electrons

  3. Number of neutrons

  4. Number of ions

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Correct Option: A
Explanation:

The number of protons in an atom determines what element you have. For instance hydrogen has one proton, carbon has six.

If number of electrons in an atom is 8 and number of protons is also 8, then give the atomic number of atom and the charge on the atom.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. (i) Atomic number = 8, (ii) Charge = 0

  2. (i) Atomic number = 4, (ii) Charge = 0

  3. (i) Atomic number = 8, (ii) Charge = +1

  4. (i) Atomic number = 4, (ii) Charge = +1

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Correct Option: A
Explanation:

Atomic number is equal to number of protons i.e. 8. Since number of protons is equal to number of electrons i.e. 8, therefore charge on the atom is 0.

The charge on a proton is ___________.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $-1602\times10^{-19}C$

  2. $1.602\times10^{-19}C$

  3. $0$

  4. None of the above

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Correct Option: B
Explanation:

The charge on protons is equal to $1.602\times10^{-19}C$

Elements are defined by the number of _______ they possess.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. electrons

  2. protons

  3. neutrons

  4. atoms

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Correct Option: B
Explanation:

Elements are defined by the number of protons they possess.

Absolute mass of a proton is equal to __________.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $9.109\times10^{-31}$ kg

  2. $-1.602\times10^{-31}$ kg

  3. $1.672\times10^{-27}$ kg

  4. $1.674\times10^{-27}$ kg

Show answer
Correct Option: C
Explanation:

The mass of proton is equal to $1.672\times10^{-27}$ kg.


Hence the correct option is C.

Absolute mass of electron is equal to __________.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $9.109\times10^{-31}$ kg

  2. $-1.602\times10^{-31}$ kg

  3. $1.672\times10^{-27}$ kg

  4. $1.647\times10^{-27}$ kg

Show answer
Correct Option: A
Explanation:

The mass of an electrons is $9.109\times10^{-31}$ kg.


Hence the correct option is A.

Absolute mass of neutrons is ____ .

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $9.109\times10^{-31}$ kg

  2. $-1.602\times10^{-31}$ kg

  3. $1.672\times10^{-27}$ kg

  4. $1.674\times10^{-27}$ kg

Show answer
Correct Option: D
Explanation:

The mass of neutrons is $1.674\times10^{-27}$ kg

An atom does not carry any electric charge because it _____________.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. has an equal number of charged and non charged particles

  2. has neutrons in their nuclei

  3. has an equal number of electrons and protons, hence positive and negative charge gets neutralized.

  4. has an equal number of neutrons and protons

Show answer
Correct Option: C
Explanation:

Equal number of negatively charged electrons and positively charged protons would give a neutral atom which would thus not have any electric charge.

The number of protons in calcium is :

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $20$

  2. $21$

  3. $22$

  4. $23$

Show answer
Correct Option: A
Explanation:

The atomic number is the number of protons in an atom of an element. The atomic number of calcium in the periodic table is 30 and hence calcium has 30 protons in its nucleus.