Question

electric configuration 21 to 60​

Answer 1

Explanation:

an approximate rule, electron configurations are given by the Aufbau principle and the Madelung rule. However there are numerous exceptions; for example the lightest exception is chromium, which would be predicted to have the configuration 1s2 2s2 2p6 3s2 3p6 3d4 4s2, written as [Ar] 3d4 4s2, but whose actual configuration given in the table below is [Ar] 3d5 4s1.

Note that these electron configurations are given for neutral atoms in the gas phase, which are not the same as the electron configurations for the same atoms in chemical environments. In many cases, multiple configurations are within a small range of energies and the irregularities shown above are quite irrelevant chemically.[1]

Legend

1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 5g 6s 6p 6d 6f 7s 7p 7d 8s 8p 9s 9p

1 H hydrogen: 1s1

1s1

1

2 He helium: 1s2

1s2

2

3 Li lithium: [He] 2s1

1s2 2s1

2 1

4 Be beryllium: [He] 2s2

1s2 2s2

2 2

5 B boron: [He] 2s2 2p1

1s2 2s2 2p1

2 3

6 C carbon: [He] 2s2 2p2

1s2 2s2 2p2

2 4

7 N nitrogen: [He] 2s2 2p3

1s2 2s2 2p3

2 5

8 O oxygen: [He] 2s2 2p4

1s2 2s2 2p4

2 6

9 F fluorine: [He] 2s2 2p5

1s2 2s2 2p5

2 7

10 Ne neon: [He] 2s2 2p6

1s2 2s2 2p6

2 8

11 Na sodium: [Ne] 3s1

1s2 2s2 2p6 3s1

2 8 1

12 Mg magnesium: [Ne] 3s2

1s2 2s2 2p6 3s2

2 8 2