Unit 3: Periodic Table and Periodicity of Properties

Which of the following elements is a lanthanide?

• A) Samarium
• B) Neodymium
• C) Plutonium
• D) Uranium

Answer: A) Samarium

Which element in Period 5 has the electron configuration [Kr] 5s² 4d¹⁰ 5p²?

• A) Tin
• B) Lead
• C) Indium
• D) Antimony

Answer: A) Tin

Which of the following elements is in Period 6 and has an electron configuration ending in 4f¹⁴ 5d¹⁰ 6s²?

• A) Samarium
• B) Neodymium
• C) Dysprosium
• D) Gadolinium

Answer: D) Gadolinium

Which element has the electron configuration [Xe] 6s² 4f⁶ 5d¹?

• A) Samarium
• B) Neodymium
• C) Dysprosium
• D) Gadolinium

Answer: C) Dysprosium

Which of the following is an alkali metal in Period 4?

• A) Rubidium
• B) Potassium
• C) Sodium
• D) Cesium

Answer: B) Potassium

Which element in Group 2 has the lowest ionization energy?

• A) Beryllium
• B) Magnesium
• C) Calcium
• D) Strontium

Answer: D) Strontium

Which of the following elements has the electron configuration [Ar] 4s² 3d¹⁰ 4p⁵?

• A) Chlorine
• B) Bromine
• C) Iodine
• D) Selenium

Answer: B) Bromine