Question 1

Which statement best describes Mendeleev’s periodic law?

Accepted Answer

When elements are arranged in order of increasing mass, certain sets of properties recur periodically.

Question 2

Why did Mendeleev leave gaps in his periodic table?

Accepted Answer

He believed some elements were missing and predicted their properties.

Question 3

Which of the following is a property of metals as described in the periodic table?

Accepted Answer

They are malleable and ductile.

Question 4

Which group in the periodic table contains elements that are highly reactive and commonly found as salts?

Accepted Answer

Halogens (Group VIIA)

Question 5

What is the main difference between Mendeleev’s periodic table and the modern periodic table?

Accepted Answer

Mendeleev’s table was arranged by atomic mass, while the modern table is by atomic number.

Question 6

Which of the following elements is classified as a metalloid?

Accepted Answer

Silicon

Question 7

A main-group metal tends to form which type of ion?

Accepted Answer

Cation

Question 8

Which group of elements is known for being chemically stable and mostly unreactive?

Accepted Answer

Noble gases

Question 9

Which of the following best describes the trend for main-group nonmetals in forming ions?

Accepted Answer

They tend to gain electrons and form anions.

Question 10

Which of the following equations correctly represents the formation of a 2+ ion by a Group IIA element?

Accepted Answer

$$ \mathrm{M} \rightarrow \mathrm{M}^{2+} + 2e^- $$

Question 11

Which property is most characteristic of nonmetals?

Accepted Answer

Poor conductors of heat and electricity

Question 12

Which of the following best explains why the periodic table is called 'periodic'?

Accepted Answer

The properties of elements repeat in a regular pattern when arranged by increasing atomic number.

Question 13

Which group is known as the alkaline earth metals?

Accepted Answer

Group IIA

Question 14

A halogen atom typically forms which ion when it reacts?

Accepted Answer

$$ \mathrm{X}^{-} $$

Question 15

Which of the following best describes the location of metalloids on the periodic table?

Accepted Answer

Along the zigzag line dividing metals and nonmetals

Question 16

Which of the following elements is most likely to form a 1+ ion?

Accepted Answer

Sodium

Question 17

Which of the following best describes the trend for chalcogens in forming ions?

Accepted Answer

They tend to gain two electrons to form 2- ions.

Question 18

Which of the following is a real-world application of the periodic law?

Accepted Answer

Predicting the properties of undiscovered elements based on their position in the table.

Question 19

Which of the following best describes the properties of transition metals?

Accepted Answer

Their properties are less predictable based simply on their position in the periodic table.

Question 20

Which equation represents the formation of a chloride ion from a chlorine atom?

Accepted Answer

$$ \mathrm{Cl} + e^- \rightarrow \mathrm{Cl}^- $$

The Periodic Law and the Periodic Table: Structure, Classification, and Trends

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