Question

Which one of the following transitions for a hydrogen atom causes the emission of light and which one corresponds to absorbed light? Which one has the highest energy? A. n_1 = 1 rightarrow n_2 = 2 B. n_2 = 2 rightarrow n_1 = 1 C. n_2 = 4 rightarrow n_1 = 1 D. n_1 = 2 rightarrow n_2 = 4 E. n_2 = 4 rightarrow n_1 = 2 Write the electronic configuration for a Ti atom in its ground state. Which one of the following processes is a chemical or a physical change? A. The mixing of nitrogen, oxygen, and argon gases to produce an air-like mixture. B. Burning propane to produce heat. C. The rusting of a nail made of metallic iron to iron (III) oxide. D. The addition of NaCI to water to form a solution. E. The boiling of liquid ethane to create ethane gas. (a) Write the formula for each of the following compounds formed for the following pairs. (b) Name the compound. AI, F (a) Write the formula for each of the following compounds. (b) Identify each as an ionic or a molecular compound? (c) Say the reason? Sufur hexachloride Calcium oxide

Answer 1

1] Emission of light happens when electron jumps from higher orbit to lower orbit

n2 to n1

n4 to n1

n4 to n2

emission takes place

Absorption of light happens to go from one state to next higher state

n1 to n2

n2 to n4

Highest enrgy is emitted when electron jumps from n4 to n1 state .

n4 to n1 state --- highest energy

2] Ti - 22

1s²2s²2p⁶3s²3p⁶3d²4s²  

3] Physical change :

A , D , E

Chemical change:

B , C

4] Al ---- +3

F ----- -1

AlF3 ---- Aluminium fluoride

5] SCl6 - Molecular compound [ Not dissociates in water ]

CaO - Ionic compound [ Dissociates into ions when dissolved in water ]