The element Cu with atomic number 29 undergoes chemical reaction to form an ion with oxidation number +2. a) Write down the subshell electronic configuration of this ion? b) Can this element show variable valency? Why? c) Write down the chemical formula of one compound formed when this elemrnt reacts with chlorine (Cl_17)

What type of questions asked from the lesson of magnetic effect of electric current 

Wavelength of green light is

A) 400-450 nm

B) 500-550 nm

C) 660-720 nm

D) 720-800 nm

What is the difference between anaerobic & aerobic respiration? Name some organism that uses the aerobic mode of respiration?

What are the main components of our environment? Explain each of them briefly.

What are examples of hydrotropism plants?