# Chemistry: orbital 2

struggle with those Qs.

Pls help~

1. You are watching a show on the cooking channel where a microwave oven is being used. For this particular oven the radiation has a wavelength of 12.0 cm. Calculate the energy of one photon coming from this oven.

12.64 x10^-26 J

1.66 x10^-26 J

1.66 x10^-24 J

1.66 x 10^-32 J

2.An atom of sulfur has how many unpaired electrons?

3

1

2

4

3. Which element has the following electron configuration 1s22s22p63s2?

Ne

Mg

Na

Al

4. In the following list, which ground state configuration does NOT exist?

[Ar]4s23d4

[Ar]4s13d5

[Xe]5s25p1

[Xe]6s24f1

5.The electronic configuration for the element having atomic number (Z) = 35 and atomic mass numer = 80 is

1s2 2s2 2p6 3s2 3p6 4s2 4p5

1s2 2s2 2p6 3s2 3p6 4s2 3d5

1s2 2s2 2p6 3s2 3p5

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5

6.The element having atomic number (Z) = 35 and atomic mass number = 80, has how many valence electrons?

5

4

6

7

What is the frequency, expressed in sec-1, for radiation that has an energy of 3.371 10-19 joules per photon?

5.893 10-7 sec-1

1.966 10-15 sec-1

1.697 1015 sec-1

5.087 1014 sec-1

### 1 個解答

• 最愛解答

1.

Wavelength, λ = 12 cm = 0.12 m

Planck constant, h = 6.63 x 10^-34 J s

Speed of light = 3 x 10^8 m s^-1

Energy of one photon

= hc/λ

= (6.63 x 10^-34) x (3 x 10^8) / 0.12

= 1.66 x 10^-24 J

2.

The electronic configuration of a sulphur atom is :

1s^2 2s^2 2p^6 3s^2 3p^4

Electrons in the orbitals of the inner shells and those in the 3s orbital are paired up. The 3p orbitals should be :

3px^2 3py^1 3pz^1

Number of unpaired electrons = 2

3.

Number of electrons in the atom of this element = 2

It is a Group II element. Only Mg belongs to Group II among the four given elements.

Hence, it is Mg.

4.

[Xe] 5s^2 4p^1 does not exist.

After filling 5s orbital, 4d orbitals are filled instead of 4p orbitals. Thus it should be :

[Xe] 5s^2 4d^1

5.

Electronic configuration depends on atomic number, but not mass number.

Only the following electronic configuration consists of 35 electrons :

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^5

6.

Refer to Q.5. It is a p-block element with 2 electrons in 4s orbital and 5 electrons in 4p orbitals.

Number of valence electrons = 2 + 5 = 7

7.

Energy, E = 3.371 x 10^-19 J

Planck constant, h = 6.63 x 10^-34 J s

E = hν

Frequency ν

= E/h

= (3.371 x 10^-19) / (6.63 x 10^-34)

= 5.087 x 10^14 sec^-1

資料來源： 胡雪八