Revision 1m

Calculate the energy required to excite an electron from n=2 to n=4

• A. 4.09 x 10^-19 J

• B. 5.45 x 10^-19 J

• C. 2.05 x 10⁶ J

• D. 2.74 x 10⁶ J

An element with proton number of 32 _________

• A. can be found in the s block

• B. is a transition element

• C. is located in period 4 and group 13

• D. has four valence electron

Which of the following solutions with a concentration of 0.1 M contain the highest concentration of potassium ions?

• A. Potassium iodide

• B. Potassium sulphate

• C. Potassium phosphate

• D. Potassium hypochlorite

How many nitrogen atoms are present in 28 dm³ of nitrogen at STP?

( Molar volume of gas = 22.4 L at STP; Avogadro constant = 6.02 x 10 ²³)

• A. 1.5 x 10²³ atoms

• B. 7.5 x 10²³ atoms

• C. 1.5 x 10²⁴ atoms

• A. 3.0 x 10²⁴ atoms

Choose the compound in which sulphur has the highest oxidation number

• A. SO_²

• B. SCl_²

• C. H₂SO^₃

• D. Na₂SO^₄

An experiment was carried out and the product obtained was 122 g. If the theoretical yield for the reaction was 156 g, what is the percentage yield of the product?

• A. 78.2%

• B. 128%

• C. 19.0%

• D. 190%

The first line of Balmer series has a wavelength of 656.3 nm. Calculate its frequency.

(Speed of light = 3 x10 ⁸)

• A. 5.57 x 10¹⁴ s^-1

• B. 4.57 x 10¹³ s^-1

• C. 4.57 x 10¹⁴ s^-1

• D. 5.57 x 10¹³ s^-1

Choose the CORRECT statement about ionic bond

• A. The difference in their electronegativity must be equal

• B. Both of the atom must be metal or non metal

• C. Each atom must achieve octet configuration

• D. The bonds are intermediate between single and double bond

Resonance structure of carbonate ion are shown below. Choose the FALSE statement about resonance structure.

• A. C–O bond lengths are identical experimentally

• B. Resonance arises when two or more Lewis structures with similar atom configurations but distinct electron distributions can be written.

• C. Each anticipates the formation of one carbon–oxygen double bond and two carbon–oxygen single bonds

• D. Resonance structures

  are capable of describing delocalized electrons that can be expressed by a single Lewis formula with an integral number of covalent bonds.

Why do the melting point and boiling point of elements decrease when going down the group?

• A. The increase in the atomic size

  down the group will weaken the attraction force between the atoms. Therefore, less heat energy is

  required to overcome the attraction forces between the metal atoms.

• B. The decrease in the atomic size

  down the group will weaken the attraction force between the atoms. Therefore, less heat energy is

  required to overcome the attraction forces between the metal atoms.

• C. The increase in the atomic size

  down the group will strengthen the attraction force between the atoms. Therefore, less heat energy is

  required to overcome the attraction forces between the metal atoms.

• D. The decrease in the atomic size

  down the group will strengthen the attraction force between the atoms. Therefore, less heat energy is

  required to overcome the attraction forces between the metal atoms.