First, this article gives you 20 periodic table MCQs that suit moderate-level exam practice. Moreover, each question comes with a correct answer and a clear Extra Information note. As a result, students learn groups, periods, element properties, and periodic trends in a simple way. Besides, aspirants of RRB NTPC, SSC, and UPSC can use these questions for quick revision. For example, you can attempt five questions at a time and check your score. Next, read every explanation, even when you answer correctly. Also, note the facts that surprise you and revise them later. In short, regular practice with these chemistry MCQs builds speed, accuracy, and confidence.
Development and Structure of the Modern Periodic Table
Q1
Which scientist arranged elements by increasing atomic mass and left gaps for undiscovered elements?
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Answer: C) Dmitri Mendeleev
First, Mendeleev published his table in 1869. Moreover, he predicted elements such as gallium and germanium before anyone discovered them. As a result, scientists trusted his arrangement. However, his table had a few mismatches in atomic mass order. Finally, later work fixed those issues using atomic number.
Q2
Whose X-ray experiments showed that atomic number, not atomic mass, should order the elements?
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Answer: A) Henry Moseley
In fact, Moseley studied the X-ray spectra of elements in 1913. Also, he found that X-ray frequency relates to atomic number. Therefore, the modern periodic law uses atomic number instead of atomic mass. For example, this change placed tellurium before iodine correctly. Overall, his work gave the table a firmer base.
Q3
How many groups and periods does the modern periodic table have?
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Answer: D) 18 groups and 7 periods
First, groups run vertically from 1 to 18. Besides, periods run horizontally from 1 to 7. Because of this, every element has a fixed group and period. However, the lanthanides and actinides sit in separate rows below the main table. Finally, these rows keep the table compact and easy to read.
Q4
Which block contains iron, copper, and zinc?
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Answer: B) d-block
Also, d-block elements fill the d orbitals and occupy groups 3 to 12. Moreover, iron, copper, and zinc belong to this block. As a result, many of these metals form coloured compounds. In contrast, s-block metals usually form colourless compounds. Thus, the block name helps you predict element behaviour.
Q5
Which noble gas sits in period 3?
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Answer: A) Argon
In fact, argon has atomic number 18 and sits in group 18. Furthermore, it makes up about 0.93% of Earth’s atmosphere. For this reason, argon is the third most abundant gas in air. Meanwhile, neon sits in period 2, and krypton sits in period 4. Overall, noble gases show very low chemical reactivity.
Periodic Trends in Chemistry MCQs
Q6
What happens to atomic size across a period from left to right?
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Answer: C) It generally shrinks
Because nuclear charge rises across a period, electrons feel a stronger pull. Also, new electrons enter the same shell. As a result, atoms become smaller. For example, sodium atoms are larger than chlorine atoms. Thus, atomic size generally shrinks from left to right.
Q7
Which element has the highest electronegativity?
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Answer: D) Fluorine
In addition, fluorine scores about 3.98 on the Pauling scale. Next, oxygen follows with about 3.44. Therefore, fluorine pulls shared electrons more strongly than any other element. However, most noble gases have no standard values because they rarely form bonds. Finally, electronegativity generally rises across a period and falls down a group.
Q8
Which element has the highest first ionisation energy?
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Answer: B) Helium
For instance, helium holds its two electrons very close to the nucleus. Also, those electrons have no inner shells to shield them. As a result, removing one electron needs a huge amount of energy. In contrast, caesium loses its outer electron easily. Overall, ionisation energy falls down a group.
Q9
How does metallic character change down a group?
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Answer: A) It generally increases
Also, atoms get bigger down a group. Consequently, outer electrons sit farther from the nucleus. Because of this, atoms lose electrons more easily. For example, potassium reacts more vigorously with water than lithium. In short, this trend explains why alkali metals grow more reactive down the group.
Q10
Which term describes elements with mixed metal and non-metal properties?
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Answer: B) Metalloids
Instead of acting like pure metals, metalloids show mixed behaviour. For example, silicon and germanium belong to this group. Furthermore, these elements conduct electricity better than non-metals but worse than metals. As a result, engineers use silicon in semiconductors. Finally, exam questions often ask for examples of metalloids.
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Groups and Families of Elements MCQs
Q11
Lithium, sodium, and potassium belong to which group?
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Answer: C) Group 1
Because they hold one outer electron, alkali metals lose it very easily. Also, they react strongly with water to form hydroxides and hydrogen gas. For this reason, people store sodium under oil. However, hydrogen sits in group 1 but is not an alkali metal. Thus, remember this exception for the exam.
Q12
Which halogen is a liquid at room temperature?
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Answer: D) Bromine
First, bromine is one of only two elements that stay liquid at room temperature. Also, mercury is the other one. Therefore, bromine stands out in group 17. Meanwhile, fluorine and chlorine are gases, and iodine is a solid. In short, halogens show a clear change in state down the group.
Q13
Which element belongs to the actinide series?
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Answer: B) Uranium
In fact, uranium has atomic number 92 and belongs to the actinides. Moreover, every actinide is radioactive. For example, uranium and thorium occur naturally. In contrast, cerium, europium, and gadolinium belong to the lanthanide series. Thus, atomic numbers 89 to 103 mark the actinides, while 57 to 71 mark the lanthanides.
Q14
Magnesium and calcium belong to which family?
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Answer: A) Alkaline earth metals
Additionally, group 2 elements hold two electrons in their outer shell. As a result, they form +2 ions. For instance, calcium forms Ca²⁺ in many compounds. However, these metals react less vigorously than alkali metals. In summary, calcium, magnesium, and barium all follow this pattern.
Q15
Which group 17 element do people commonly use to disinfect drinking water?
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Answer: C) Chlorine
For example, water plants add chlorine to kill germs. Also, chlorine has seven electrons in its outer shell. Because of this, it gains one electron easily. Still, chlorine gas is toxic and needs careful handling. Finally, it forms chloride ions such as Cl⁻ in common salt.
Element Symbols, Uses and Important Facts MCQs
Q16
Which metal stays liquid at room temperature?
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Answer: D) Mercury
Although mercury is a metal, it stays liquid at room temperature. Also, its symbol Hg comes from the Latin word hydrargyrum. Therefore, the symbol does not match its English name. However, mercury is toxic, so people handle it with great care. Finally, thermometers once used it widely.
Q17
Which noble gas do people use to fill party balloons?
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Answer: A) Helium
Because helium does not burn, people prefer it over hydrogen for balloons. Also, helium has atomic number 2 and the symbol He. Moreover, hospitals use liquid helium to cool MRI magnets. In contrast, neon gives a bright red-orange glow in signs. Thus, each noble gas has its own special use.
Q18
Which element does the symbol K represent?
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Answer: B) Potassium
Although the English name starts with P, the symbol is K. Also, the symbol comes from the Latin name kalium. For example, Na for sodium comes from natrium, and Fe for iron comes from ferrum. Therefore, students should learn these symbols as a set. Finally, potassium belongs to group 1, the alkali metals.
Q19
Which element is the most abundant in the universe?
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Answer: C) Hydrogen
Overall, hydrogen makes up about three-quarters of the universe’s ordinary matter by mass. Furthermore, helium forms most of the remaining quarter. As a result, stars mainly fuse hydrogen into helium. However, hydrogen is much rarer in Earth’s crust. Finally, hydrogen sits at the top of the table with atomic number 1.
Q20
Which element does the symbol Au represent?
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Answer: D) Gold
Because Au comes from the Latin word aurum, students often link it with gold. Also, gold has atomic number 79 and sits in group 11. As a result, it belongs to the d-block, just like copper and silver. In contrast, platinum sits in group 10. Finally, gold resists corrosion, so people use it in jewellery and electronics.
Final Thoughts on Periodic Table MCQs
Overall, these periodic table MCQs cover history, structure, trends, groups, and useful element facts. Moreover, you saw how Mendeleev and Moseley shaped the modern table. Next, you practised atomic size, electronegativity, and ionisation energy trends. Also, you reviewed key families such as alkali metals, halogens, and noble gases. Therefore, revise the questions again after two or three days. In addition, read every Extra Information note and write the key facts in your own words. Then, take a timed test to improve your speed for RRB NTPC, SSC, and UPSC exams. Finally, keep practising with a smile, because steady effort builds confidence and good marks.