Chemistry 9th Chap 4 : Topic 1 - Maryam Publications

Chemistry Chapter 4 : Topic 1

Modern Periodic Table

1 / 20

The modern periodic table is constructed on a fundamental principle that elements are arranged systematically. Which statement correctly defines this arrangement?

A) Elements are arranged according to increasing atomic mass because it determines chemical behavior directly.

B) Elements are arranged randomly but grouped based on similar physical states at room temperature.

C) Elements are arranged according to discovery date and grouped alphabetically for convenience.

D) Elements are arranged in order of increasing atomic number in periods and groups based on similar properties.

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In the modern periodic table, the position of an element is mainly determined by its atomic number. This means that elements are arranged according to:

A) Number of neutrons in the nucleus

B) Number of protons in the nucleus

C) Total number of nucleons

D) Mass number only

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A student observes that elements in the same group show similar chemical properties. This similarity is mainly due to:

A) Same atomic masses

B) Same number of valence electrons

C) Same number of shells

D) Same number of neutrons

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Periods in the periodic table represent:

A) Horizontal rows arranged by increasing atomic number

B) Random placement of elements based on density

C) Diagonal arrangements of elements with similar mass

D) Vertical columns with similar properties

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Which statement best explains why the modern periodic table replaced the Mendeleev periodic table?

A) Because it only includes metals

B) Because it is based on atomic number instead of atomic mass

C) Because it uses alphabetical order of elements

D) Because it ignores chemical properties

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When elements are arranged in increasing atomic number, periodic repetition of properties occurs because:

A) Neutrons repeat in pattern

B) Density follows a fixed pattern

C) Electron configuration repeats periodically

D) Mass number remains constant

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Group 1 elements (alkali metals) show similar properties because they all:

A) Have identical atomic masses

B) Have full outer shells

C) Have one electron in their outermost shell

D) Have two electrons in the outer shell

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If an element has atomic number 11, its position in the periodic table is determined by:

A) Number of protons (11)

B) Number of neutrons only

C) Number of isotopes

D) Its mass number

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The arrangement of elements in groups leads to:

A) Different chemical properties in each group

B) Similar chemical properties within a group

C) Decrease in atomic size only

D) Random distribution of metals and non-metals

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Which of the following best describes a period in the periodic table?

A) A vertical column with identical chemical behavior

B) A horizontal row where atomic number increases from left to right

C) A set of non-metals only

D) A group of elements with identical mass numbers

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The modern periodic table is considered more accurate than earlier versions because it:

A) Uses only physical state of elements

B) Is based on proton number which is a fundamental property

C) Ignores chemical properties

D) Is arranged randomly for flexibility

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Elements in the same period have the same:

A) Number of electron shells

B) Number of valence electrons

C) Atomic mass

D) Chemical reactivity

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Why are noble gases placed in Group 18?

A) They have full outer electron shells

B) They have lowest atomic mass

C) They contain only one electron shell

D) They are highly reactive

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The periodic law states that properties of elements are periodic functions of:

A) Density

B) Melting point

C) Atomic mass

D) Atomic number

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If elements were arranged by atomic mass instead of atomic number, what major issue would arise?

A) Elements would lose electrons

B) No groups would form

C) Periods would disappear completely

D) Anomalies in element placement would occur

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The similarity of properties in a group is mainly due to similarity in:

A) Atomic mass

B) Valence electron configuration

C) Number of isotopes

D) Number of protons

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Which statement correctly describes the trend across a period?

A) Elements become identical

B) Atomic number decreases

C) Valence electrons remain constant

D) Atomic number increases from left to right

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The main purpose of arranging elements in the periodic table is to:

A) Memorize elements easily

B) Classify elements based on recurring properties

C) Separate metals and non-metals completely

D) Group elements randomly

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Which of the following best explains why hydrogen is placed in Group 1 despite being a non-metal?

A) It has highest atomic mass in group

B) It has one valence electron

C) It has full outer shell

D) It is a metal like sodium

20 / 20

The arrangement of elements in the periodic table helps scientists mainly to:

A) Change atomic structure of elements

B) Convert elements into compounds

C) Increase atomic number artificially

D) Predict element properties and behavior

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