Periodicity Review (Topic 3)

An element is in period 3 and group 15 of the periodic table. How many electrons are present in the highest occupied energy level of this element?

• 3

• 5

• 13

• 15

Which species has the same configuration of electrons as the Mg²⁺ ion?

• Na atom

• F⁺ ion

• Ne atom

• O^- ion

Which element is a transition metal?

• lead, Pb

• gallium, Ga

• strontium, Sr

• iron, Fe

Which is the correct electron configuration for an atom with the atomic number 34?

• 1s²2s²2p⁶3s²3p⁶3d¹⁰

• 1s²2s²2p⁶3s²3p⁶3d¹⁰4p⁶

• [Ar]4s²3d¹⁰4p⁴

• [Ar]3d¹⁰4p⁶

Which best describes the trends of electronegativity values within the periodic table?

• The values increase across a period (from left to right) and decrease down a group.

• The values increase across a period (from left to right) and increase down a group.

• The values decrease across a period (from left to right) and decrease down a group.

• The values decrease across a period (from left to right) and increase down a group.

Which properties increase in value when descending group 1?

I. First ionization energy

II. Atomic radius

III. Reactivity with water

• I and II only

• I and III only

• II and III only

• I, II and III

The first ionization energies for three consecutive elements in the periodic table are 1251, 1521, and 419 kJ mol^-1 respectively. Which elements have these values?

• carbon, nitrogen, oxygen

• neon, sodium, magnesium

• sodium, magnesium, aluminum

• chlorine, argon, potassium

Which is correct when the ionic or atomic radii are compared?

• Ca²⁺ < Ca⁺

• Cl^- < Cl

• Na < Na⁺

• B < C

Which factors lead to an element having a high first ionization energy?

I. Completely filled outer energy level

II. Small atomic radius

III. High number of completely filled inner energy levels

• I and II only

• I and III only

• II and III only

• I, II and III

Which statement about a trend within the periodic table is correct?

• Melting points decrease in group 1 from lithium to cesium.

• Atomic radii increase in period 3 from sodium to chlorine.

• Electronegativity values increase in group 17 from fluorine to iodine.

• First ionization energies increase in group 14 from carbon to lead.