Answer:
a) the atomic number is 15
b) the mass number is 15+16 = 31
c) element is phosphorus
d)Group 15 period 3
Yes it does, its derived from the greek name for beryl, or beryllo
There are two types of 'quantities' namely: scalar and vector
A 'vector' is a quantity that has both magnitude and direction whereas a 'scalar' has only magnitude.
Magnitude is a measure or the size of the quantity or object.
In the given example of the vector: '75 mph to the north'
Magnitude is the number 75 mph
Direction is north
Ans C)
When an electron transit from lower level to higher level it emits energy
When an electron transit from higher level from a lower level it absorbs energy
n=3 to n=5, : absorption
n=1 to n=3, : absorption
n=3 to n=2, : emission
n=2 to n=1 : emission
the highest energy means highest wave number
wave number = Rh (1/ n1^2 - 1/n2^2)
Rh = 1.1 X 10^7 m^-1
1) n=3 to n=5
wavenumber = Rh ( 1/ 9 - 1/ 25) = 0.071 Rh
2) n=1 to n=3
wavenumber = Rh ( 1- 1/9 ) = 0.89 Rh
3) n=3 to n=2
wavenumber = Rh ( 1/4 - 1/9) = 0.139 Rh
4) n=2 to n=1
wavenumber = Rh ( 1- 1/4) = 0.75 Rh
Thus for 2) n=1 to n=3 energy will be maximum
