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M.Sc Chemistry Atoms — practice questions

Explore 32 free Atoms questions in M.Sc Chemistry Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

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Atoms questions and exercises with answers

Showing questions 1–30 of 32.

The modern periodic law states that the physical and chemical properties of elements are periodic functions of:Read the answer and worked solution →Elements of the modern periodic table are classified into how many blocks based on the differentiating electron?Read the answer and worked solution →Across a period from left to right, the atomic radius generally:Read the answer and worked solution →Which element has the highest first ionization energy in period 2?Read the answer and worked solution →Which of the following arrangements is in correct order of increasing electronegativity (Pauling scale)?Read the answer and worked solution →The element with electronic configuration $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^3$ belongs to which group and period?Read the answer and worked solution →Order the atomic models as they were proposedRead the answer and worked solution →Match each scientist to their modelRead the answer and worked solution →Match each model to what it could NOT explainRead the answer and worked solution →True or false: Rutherford's modelRead the answer and worked solution →True or false: Bohr's modelRead the answer and worked solution →Complete the reason Bohr's model failsRead the answer and worked solution →Which model does this belong to?Read the answer and worked solution →Match each quantum number to what it is calledRead the answer and worked solution →True or false: the quantum mechanical modelRead the answer and worked solution →Order the structure: from atom down to electronRead the answer and worked solution →Complete the (n + l) ruleRead the answer and worked solution →True or false: orbital energiesRead the answer and worked solution →Match each rule to what it forbids or requiresRead the answer and worked solution →Tap every statement Hund's rule requiresRead the answer and worked solution →The fundamental particlesRead the answer and worked solution →Assertion and reasonRead the answer and worked solution →Two are true, one is notRead the answer and worked solution →Three of these are wrong. Find the one that holds.Read the answer and worked solution →Which principle is being described?Read the answer and worked solution →Flip and pair: symbol with meaningRead the answer and worked solution →Spot the one that does not belongRead the answer and worked solution →Tap every statement true of the Schrodinger modelRead the answer and worked solution →Reading the models backRead the answer and worked solution →Assertion and reason: filling orbitalsRead the answer and worked solution →

Worked practice questions

The modern periodic law states that the physical and chemical properties of elements are periodic functions of:

  1. Atomic mass
  2. Atomic radius
  3. Atomic number
  4. Number of neutrons
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Correct answer: C. Atomic number

Modern (Moseley's) periodic law: properties of elements are periodic functions of their **atomic number** ($Z$). This replaced Mendeleev's original law which was based on atomic mass. Why atomic number wins: it explains chemistry better (electronic structure follows $Z$, not mass) and resolves Mendeleev's anomalies (the Ar/K and Te/I pairs whose mass-order disagrees with chemistry-order).

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Elements of the modern periodic table are classified into how many blocks based on the differentiating electron?

  1. 2 (s and p)
  2. 4 (s, p, d, f)
  3. 3 (s, p, d)
  4. 5 (s, p, d, f, g)
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Correct answer: B. 4 (s, p, d, f)

**Four blocks** based on which subshell the differentiating electron enters: - **s-block**: Groups 1 and 2 (Li, Na, K, Be, Mg, Ca, etc.) - **p-block**: Groups 13 to 18 (B, C, N, O, F, halogens, noble gases) - **d-block**: Groups 3 to 12 (transition metals) - **f-block**: Lanthanides and actinides (separated below the main table) No g-block has been confirmed experimentally yet, though it's predicted for superheavy elements ($Z > 120$).

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Across a period from left to right, the atomic radius generally:

  1. Decreases
  2. Remains constant
  3. Increases
  4. First increases then decreases
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Correct answer: A. Decreases

Atomic radius **decreases** from left to right across a period. Why: nuclear charge ($Z$) increases by 1 as you move right, pulling electrons closer. The added electron enters the same shell so screening barely increases — the net effect is stronger attraction and smaller radius. Across period 2: Li (152 pm) → Be → B → C → N → O → F (72 pm). Roughly halves. Down a group, atomic radius *increases* (electrons go into higher principal shells, further from nucleus).

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Chemical EquilibriumEquilibriumSolid StateClassification of Elements and PeriodicityAlkenesIdeal and Non-Ideal SolutionsIdeal SolutionsNon-Ideal Solutions