STPM PERIODICITY

Among which of the following pairs of the Period 3 elements is the difference in boiling point the greatest?

• Silicon and argon

• Sodium and argon

• Sodium and silicon

• Aluminium and chlorine

Which of the following statements is true regarding the oxides of the elements in Period 3 (sodium to chlorine) of the Periodic Table?

• Sodium oxide is the strongest base because sodium is the most electropositive element in Period 3

• Going across Period 3 the properties of the oxides changes from base to acid because the bond between the element and oxygen gets stronger.

• Aluminium oxide is amphoteric because it is in Group 13.

• Oxide of phosphorus forms the strongest acid because it is the most soluble in water.

Going across Period 3 (sodium to chlorine) in the Periodic Table

• The electronegativity of the elements decreases.

• The ionisation energy of the element decreases

• The standard electrode potential of the elements increases.

• The strength of the elements as reducing agents increases.

The proton numbers of elements X, Y and Z are 14, 19 and 26 respectively. Which of the following statements is true with regard to X, Y and Z?

• X is a d-block element.

• Y is a strong oxidizing agent

• Z exhibits only one oxidation state in its compounds.

• The oxide of X with the formula of XO₃^- exists as a polymer.

Which of the following is true for the elements in the Periodic Table?

• There are fewer metals compared to non-metals.

• The size of the atoms increases with increasing nucleon number.

• The metallic property increases on going down a group.

• The reactivity increases on going down a group.

An oxide of G has a boiling point 2230°C. It dissolves in aqueous sodium hydroxide solution but not in water and acid. Oxide G is

• PbO₂

• P₂O₅

• SiO₂

• Al₂O₃

The first ionisation energy generally increases across a period in the Periodic Table. Which statement explains why the first ionisation energy of sulphur is lower than that of phosphorus?

• The electrons in the p orbitals of sulphur experience greater electrostatic repulsion than that of phosphorus

• The sulphur atom has more electrons than phosphorus atom.

• The S-S bond is weaker than the P-P bond.

• The size of S₈ molecule is bigger than P₄ molecule.

The properties of elements can be deduced from electronic configurations. Which statement is true about Na⁺ ion, Cl^- ion, Ar atom and K⁺ ion?

• Na⁺ ion is bigger than Cl^- ion.

• The charge density of Na⁺ ion is lower than that of Cl^- ion.

• The ionisation energy of K⁺ ion is higher than that of Na⁺ ion.

• Cl^- ion, K⁺ ion and Ar atom have the same electronic configuration.

Tags

NGSS.HS-PS1-1

The acid-base properties of oxides are related to their structure and chemical bonding. Which oxide dissolved in water to form an acidic solution?

• MgO

• Al₂O₃

• . SiO₂

• SO₃

Which statement explains the difference in the first

ionisation energies between beryllium and boron?

• Boron atom has more valence electrons.

• Boron atom has a greater shielding effect.

• Beryllium atom has a more stable electronic

  configuration.

• The 2p electron in boron atom is at a higher

  energy level than the 2s electron in beryllium atom