$$ns^1$$ \, \text{or} \, $$ns^2$

Question 1

Which of the following statements best describes the Modern Periodic Law?

Accepted Answer

The physical and chemical properties of the elements are periodic functions of their atomic numbers.

Question 2

Which scientist is credited with the first publication of the Periodic Law based on atomic weights?

Accepted Answer

Dmitri Mendeleev

Question 3

What is the general outer electronic configuration of the s-block elements?

Accepted Answer

$$ns^1$$ \, 	ext{or} \, $$ns^2$

Question 4

Which of the following elements would have the largest atomic radius?

Accepted Answer

K

Question 5

Why does the atomic radius decrease across a period from left to right?

Accepted Answer

Because the effective nuclear charge increases, pulling electrons closer to the nucleus.

Question 6

Which of the following is the correct order of increasing metallic character: Si, Be, Mg, Na, P?

Accepted Answer

P \u003c Si \u003c Be \u003c Mg \u003c Na

Question 7

Which of the following species is smallest in size?

Accepted Answer

$$Al^{3+}$$

Question 8

Which property generally increases across a period from left to right in the Periodic Table?

Accepted Answer

Ionization enthalpy

Question 9

Which of the following elements has the most negative electron gain enthalpy?

Accepted Answer

Cl

Question 10

What is the IUPAC systematic name for the element with atomic number 120?

Accepted Answer

Unbinilium

Question 11

Which of the following best explains why cations are smaller than their parent atoms?

Accepted Answer

Cations have fewer electrons, so the same nuclear charge pulls the electrons closer.

Question 12

Which block of elements is characterized by the filling of (n-1)d orbitals?

Accepted Answer

d-block

Question 13

Which of the following oxides is most acidic?

Accepted Answer

Cl_2O_7

Question 14

Which element would you expect to have the highest electronegativity?

Accepted Answer

Fluorine

Question 15

Which of the following best describes the trend in ionization enthalpy down a group?

Accepted Answer

It decreases due to increasing atomic radius and shielding effect.

Question 16

Which of the following is a characteristic property of transition elements?

Accepted Answer

They form colored ions and exhibit variable oxidation states.

Question 17

Which of the following elements is a metalloid?

Accepted Answer

Silicon

Question 18

Which of the following best explains the diagonal relationship in the periodic table?

Accepted Answer

The first element of a group resembles the second element of the next group due to similar size and charge/radius ratio.

Question 19

Which of the following is the correct formula for the compound formed between aluminium and sulphur?

Accepted Answer

Al_2S_3

Question 20

Which of the following statements about the periodic trends in chemical reactivity is correct?

Accepted Answer

Reactivity is highest at the two extremes of a period.

Classification of Elements and Periodicity in Properties: Structured Study Notes

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