The Periodic Table — Practice · Grade 11 Science

Chapter: Atoms, Electrons & Periodicity

What this practice covers

By the end of The Periodic Table you should be able to:

10 questions, multiple choice, numeric and written answer, each with a worked explanation.

Vocabulary used: period, group (family), block (s, p, d, f), metal, nonmetal, metalloid, transition metals, noble gases.

Problem 1

A vertical column of the periodic table is called a…
  1. period
  2. group (family)
  3. block
  4. series
Answer and explanation

group (family)

Vertical columns are groups, or families; horizontal rows are periods.

Problem 2

Elements in the same group have similar chemical properties mainly because they have the same number of…
  1. neutrons
  2. protons
  3. valence electrons
  4. energy levels
Answer and explanation

valence electrons

Matching valence-electron counts give group-mates similar bonding behavior.

Problem 3

Selenium is a main-group element in Group 16. How many valence electrons does it have?
Answer and explanation

6

For main-group elements, valence electrons = group number − 10 = 16 − 10 = 6.

Problem 4

Which part of the periodic table contains the transition metals?
  1. Group 17 (the halogens)
  2. Group 18 (the noble gases)
  3. Groups 1–2 (s-block)
  4. The d-block, groups 3–12
Answer and explanation

The d-block, groups 3–12

The transition metals make up the d-block in the center of the table, groups 3–12.

Problem 5

Explain the difference between a period and a group, including what each one tells you about an atom's electrons.
Answer and explanation

A period is a horizontal row; every element in it has its outermost electrons in the same highest energy level (same n). A group is a vertical column; its elements all have the same number of valence electrons, which is why they share similar chemistry.

Problem 6

Silicon lies along the staircase line and is used to make semiconductors. It is best classified as a…
  1. metalloid
  2. noble gas
  3. metal
  4. nonmetal
Answer and explanation

metalloid

Elements along the staircase, like silicon, are metalloids with in-between properties that make them useful semiconductors.

Problem 7

A main-group element has outer configuration 4s². What broad position fits? Show the reasoning, not just the conclusion.
Hints

Group labels 1–18 differ from valence-electron counts.

Answer and explanation

Period 4, group 2, for the corresponding neutral ground-state main-group atom.

Problem 8

Why cannot every transition-metal behavior be predicted by the simple main-group valence rule?
Hints

State what the supplied observations or conditions establish, and separate that from any assumption.

Answer and explanation

d-electron involvement and variable oxidation states complicate those patterns.

Problem 9

Patterns need their domain and important exceptionsPatterns need their domain and important exceptionsGroupOuter main-group patternSelected example1ns¹Na: 3s¹2ns²Mg: 3s²17ns²np⁵Cl: 3s²3p⁵18ns²np⁶*Ar: 3s²3p⁶*He is 1s²; a full first shell contains two electrons.
Original main-group pattern table with n denoting the outer principal level, not an electron count multiplier.
Interpret the supplied visual. Why is helium grouped with noble gases despite having only two electrons?
Answer and explanation

Its first shell is filled by two electrons. The relevant pattern is a filled available valence shell, not a requirement for eight in every element.

Main-group columns often share an outer-shell electron pattern. Group 1 typically has ns¹ and Group 17 ns²np⁵; Group 18 has a filled outer shell, with helium’s 1s² as a key exception to an eight-electron slogan. Transition elements require more attention to nearby d states and variable oxidation numbers. The pattern helps predict likely bonding behavior, but it does not prescribe an atom’s objective or supply a complete reaction energy calculation.

Its first shell is filled by two electrons. The relevant pattern is a filled available valence shell, not a requirement for eight in every element.

Response criteria

  • Interpret labels, structures, axes, units and directions correctly.
  • Explain the chemistry relationship or mechanism.
  • Respect stated assumptions and distinguish observation from inference.

Problem 10

Element A has outer configuration 3s²3p⁵ and B has 4s²4p⁵. Identify their main-group relationship, explain one likely similarity and one reason properties need not match.
Answer and explanation

Both fit Group 17. Similar valence patterns support related bonding tendencies, while B has an additional occupied shell and different nuclear charge/shielding. Exact radius, energy and reaction behavior need the specified species and conditions.

Both fit Group 17. Similar valence patterns support related bonding tendencies, while B has an additional occupied shell and different nuclear charge/shielding. Exact radius, energy and reaction behavior need the specified species and conditions.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the chemical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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