Class 10 Periodic Table, Periodic Properties and Variations of Properties Mock Test (ICSE)

Topics in Periodic Table, Periodic Properties and Variations of Properties

• Modern periodic table
• Atomic size
• Ionisation potential
• Electron affinity
• Electronegativity
• Metallic and non-metallic character

Periodic Table, Periodic Properties and Variations of Properties practice questions with answers

1. Q1Multiple choice·1 mark
   Which of the following alkali metals has the largest atomic radius?

   1. (a)$Na$
   2. (b)$Li$
   3. (c)$K$
   4. (d)$Cs$
   Show answer and step marks

   1. Correct option: (d) $Cs$+1

   Answer: (d)
2. Q2Multiple choice·1 mark
   The total number of vertical columns (groups) and horizontal rows (periods) in the modern periodic table are respectively:

   1. (a)18 and 7
   2. (b)16 and 7
   3. (c)7 and 18
   4. (d)7 and 16
   Show answer and step marks

   1. Correct option: (a) 18 and 7+1

   Answer: (a)
3. Q3Multiple choice·1 mark
   As we move from left to right across a period in the modern periodic table, the metallic character of elements:

   1. (a)remains the same
   2. (b)increases
   3. (c)decreases
   4. (d)first increases then decreases
   Show answer and step marks

   1. Correct option: (c) decreases+1

   Answer: (c)
4. Q4Short answer·2 marks
   Define ionisation potential. State how it generally varies as you move from left to right across a period in the modern periodic table.
   Show answer and step marks

   1. Definition: The amount of energy required to remove an electron from a neutral isolated gaseous atom to form a positively charged gaseous ion.+1
   2. Trend: It increases across a period from left to right due to a decrease in atomic size and an increase in nuclear charge.+1

   Answer: Ionisation potential is the energy required to remove an electron from a neutral isolated gaseous atom to form a gaseous positive ion. It generally increases from left to right across a period, as atomic size decreases and nuclear charge increases.
5. Q5Short answer·2 marks
   (a) Define ionisation potential. (b) State how ionisation potential varies as one moves down a group in the periodic table and give a reason for this trend.
   Show answer and step marks

   1. (a) Definition: The amount of energy required to remove an outermost valence electron from a neutral isolated gaseous atom.+1
   2. (b) Trend: ionisation potential decreases down a group.+0.5
   3. (b) Reason: atomic size increases with each new shell and the inner shells shield the valence electrons, so the nucleus holds them less strongly despite the higher nuclear charge.+0.5

   Answer: (a) The energy required to remove the outermost electron from a neutral isolated gaseous atom. (b) It decreases down a group, because the atomic size increases and the valence electrons are farther from (and shielded from) the nucleus.
6. Q6Long answer·4 marks
   Answer the following questions regarding electron affinity: (a) Define electron affinity. (b) State the trend in electron affinity across a period from left to right and give a reason for it. (c) Explain why fluorine has a lower electron affinity than chlorine.
   Show answer and step marks

   1. (a) Electron affinity is defined as the amount of energy released when an electron is added to a neutral gaseous isolated atom to convert it into a negative ion.+1
   2. (b) Trend: electron affinity generally increases from left to right across a period.+0.5
   3. (b) Reason: nuclear charge increases and atomic size decreases, so the nucleus attracts an incoming electron more strongly.+0.5
   4. (c) Fluorine is much smaller than chlorine, so its added electron enters the compact $2p$ subshell.+1
   5. (c) The strong electron-electron repulsion there means less energy is released, so fluorine's electron affinity is lower than chlorine's.+1

   Answer: (a) The energy released when an electron is added to a neutral isolated gaseous atom to form a negative ion. (b) It generally increases across a period, because nuclear charge increases and atomic size decreases. (c) Fluorine's small size crowds the added electron into its compact 2p subshell, where electron repulsion reduces the energy released.

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