Periods and Groups - UNSOLVED PRACTICE SET
Chapter: Periodic Classification of Elements | Topic: Periods and Groups
PERIODS AND GROUPS - UNSOLVED PRACTICE SET
Topic: Periods and Groups
Multiple Choice Questions
Q1. Horizontal rows in the periodic table are called:
- Groups
- Periods
- Families
- Series
Q2. How many periods are there in the modern periodic table?
- 8
- 7
- 18
- 32
Q3. Elements in the same group have the same number of:
- Protons
- Neutrons
- Valence electrons
- Electron shells
Q4. The period number of an element is determined by:
- The number of valence electrons
- The number of electron shells
- The atomic mass
- The number of protons
Q5. Which of the following elements belongs to Group 1?
- Magnesium
- Sodium
- Aluminium
- Chlorine
Q6. The elements from atomic number 57 to 71 are placed in:
- Period 6
- Group 3
- Lanthanide series below the main table C
- Actinide series
Short Answer Questions
Q7. What is the difference between a period and a group in the modern periodic table?
Q8. Why do elements in the same group show similar chemical properties?
Q9. How many elements are present in the 2nd period? Name the first and last element of this period.
Q10. Why are the 4th and 5th periods called long periods?
Q11. Your class is arranged in rows and columns, just like the periodic table. If students with the same number of pens in their bags sit in the same column, and students in the same row have bags of similar size, explain how this is analogous to groups and periods in the periodic table.
Q12. Where are the noble gases placed in the modern periodic table? Why are they placed in Group 18?
Long Answer Questions
Q13. Describe the structure of the modern periodic table. Explain:
(a) How many periods are there and what determines the number of elements in each period?
(b) How many groups are there and what determines the group number?
(c) Why are the lanthanides and actinides placed separately at the bottom?
(d) Where are the transition elements located?
Illustrate your answer with examples.
Q14. Explain the relationship between the electronic configuration of an element and its position in the periodic table. For an element with atomic number 15, determine:
(a) Its period number
(b) Its group number
(c) The number of valence electrons
(d) Its valency
Show how you arrived at each answer.
Q15. During a school activity, you are given cards with the following elements: Li (Z=3), Be (Z=4), B (Z=5), C (Z=6), N (Z=7), O (Z=8), F (Z=9), Ne (Z=10).
(a) Arrange these cards in a horizontal row. What is this row called in the periodic table?
(b) What do all these elements have in common in terms of their electron shells?
(c) If you pick Li and Na (Z=11), where would you place Na relative to Li? What would this vertical arrangement be called?
(d) Why do Li and Na show similar chemical properties despite having different numbers of electron shells?
Numerical / Application-Based Problems
Q16. An element has the electronic configuration 2, 8, 3.
(a) What is its atomic number?
(b) In which period and group would you place it?
(c) How many valence electrons does it have? Predict its valency.
Q17. The 3rd period contains 8 elements: Na (Z=11) to Ar (Z=18).
(a) Write the electronic configuration of sodium (Na) and argon (Ar).
(b) Why does this period contain exactly 8 elements? (Hint: Consider the maximum number of electrons in the M shell)
(c) The 4th period contains 18 elements. Explain why it has more elements than the 3rd period.
Q18. A student is trying to locate three elements in the periodic table:
Table
Element Electronic Configuration
X 2, 8, 7
Y 2, 8, 8, 1
Z 2, 8, 4
(a) Determine the period and group of each element.
(b) Which two elements would show more similar chemical properties? Why?
(c) Element W has atomic number 12. In which period and group would it be placed? Would it be more similar to X, Y, or Z? Explain.