No individual atom in a sample of 1 mole of Neon has a mass of 20.18 a.m.u. because it is ?

C. Mass number of the most abundant isotope

Everyday Science · Atoms, Elements & Compounds · page 19 of 30

Atoms MCQs with Answers

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Atoms MCQs (181–190)

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181.
When the 6d orbital is complete the entering electron goes into?
Correct Answer: B. 7p
One-liner
When the 6d orbital is complete, the entering electron goes into the 7p orbital.
182.
If Aufbau rule is not followed in filling to the sub-shell then the block of which element will change in the periodic table?
Correct Answer: C. Sc (21)
One-liner
If the Aufbau rule is not followed, the block of Sc (21) will change in the periodic table because its differentiating electron enters the 3d orbital instead of the expected 4p.
183.
What is the charge of alpha particles in nuclear radiation?
Correct Answer: A. Positively charged
One-liner
Alpha particles in nuclear radiation are positively charged because they consist of two protons and two neutrons (a helium nucleus).
184.
If an electron in the hydrogen atom jumps from second to first orbit, the emitted radiation has a wavelength of?
Correct Answer: C. 4/3RH
One-liner
The wavelength of radiation emitted when an electron in a hydrogen atom jumps from the second orbit (n=2) to the first orbit (n=1) is 4/3RH.
185.
The Lyman series in hydrogen spectrum is produced when electron falls to:
Correct Answer: D. n=1
One-liner
The Lyman series in the hydrogen spectrum is produced when an electron falls to the n=1 energy level.
186.
The sample of polonium-218 has an original mass of 160 micrograms. How much of this sample will be left after three half-lives?
Correct Answer: B. 20 micrograms
One-liner
After three half-lives, the remaining mass will be 20 micrograms (160 → 80 → 40 → 20).
187.
An α-particle is?
Correct Answer: D. Helium Nucleus
One-liner
An α-particle is a Helium Nucleus, consisting of two protons and two neutrons.
188.
A radioactive decay can be represented as shown: 91Pa^233 → 92U^233 + ...... The emitted particle is a/an?
Correct Answer: B. β-particle
One-liner
The emitted particle is a β-particle (beta particle), as the atomic number increases by 1 while the mass number remains unchanged.
189.
Binding energy of Helium is ?
Correct Answer: C. 28.2 MeV
One-liner
The binding energy of Helium (He-4) is 28.2 MeV.
190.
No individual atom in a sample of 1 mole of Neon has a mass of 20.18 a.m.u. because it is ?
Correct Answer: A. Average atomic mass of Ne
One-liner
No individual neon atom has a mass of 20.18 a.m.u. because 20.18 is the average atomic mass of Ne, calculated from the weighted average of its naturally occurring isotopes.

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Atoms MCQs with Answers

Atoms MCQs (181–190)

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