Answer: Ionisation energy increases and the tendency to lose electrons decreases.
- A Ionisation energy increases and the tendency to lose electrons decreases
- B Atomic mass steadily decreases from left to right according to standard textbooks
- C The total number of electrons decreases across the period in general practice
- D Valence electrons are progressively removed across the period as frequently described
Correct answer: A. Ionisation energy increases and the tendency to lose electrons decreases
Explanation: Across a period, increasing nuclear charge holds valence electrons more tightly, reducing the tendency to form cations.
The complete modern periodic table (118 elements). Image: Cepheus et al., Public Domain, via Wikimedia Commons.
Concept context
The periodic table organises all 118 elements by atomic number and similar properties. Study periodic trends like atomic radius, ionization energy, and electronegativity, and learn how an element's position predicts its behaviour.
Read the full Classification of Elements and Periodicity in Properties notes →