True-False

Question 11 Mark

State whether the following statement is true or false:
On going down in a group of the periodic table, the number of valence electrons increases.

Answer

False.

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Question 21 Mark

State whether the following statements are true or false:
The elements in a group have consecutive atomic numbers.

Answer

False.

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Question 31 Mark

State whether the following statements are true or false:
Newlands divided the elements into horizontal rows of eight elements each.

Answer

False.

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Question 41 Mark

The elements of the same group have similar chemical properties because of same number of valence electrons. [True/ False]

Answer

True.
Explanation:
Electrons are also referred as non-valence electrons. Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level.

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Question 51 Mark

Fluorine is a non-metal with valency two. [True/ False]

Answer

False.
Explanation:
The elements in this family are fluorine, chlorine, bromine, iodine, and astatine. Halogens have 7 valence electrons, which explains why they are the most active non-metals.

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Question 61 Mark

Helium, neon and argon are inert elements. [True/ False]

Answer

True.
Explanation:
The Group 18 elements include Helium(He), Neon(Ne), Argon(Ar), Krypton(Kr), Xenon(Xe), and Radon(Rn). They are referred to as noble gases or inert gases.

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Question 71 Mark

Element with atomic number 17 belongs to $3^{rd}$ period. [True/ False]

Answer

True.
Explanation:
An element ‘a' belongs to $3^{rd}$ period and $17^{th}$ group of the periodic table.

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Question 81 Mark

State whether the following statements are true or false:
According to Mendeleev’s periodic law, the properties of elements are a periodic function of their atomic numbers.

Answer

False.

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