Question

What element does each of following electron configurations represent? please show all work

Configuration	Element
1s22s2
1s22s22p6
1s22s22p2p2p2
[Ar]4s2
[Ar]3d2d2d14s2

Answer 1

Electronic configuration of elements

Configuration 1s2 2s2                   Element - Beryllium

With 2s2 configuration in the valence shell, this element belongs to the alkaline earth metal series. Total electrons are 4. Beryllium has atomic number 4, so it fills the first two s-orbitals.

---

Configuration 1s2 2s2 2p6                    Element - Neon

With total 10 electrons, and octet configuration (8 electron's in valence shell), this is a nobel gas configuration. The atomic number 10 matches with Neon

---

Configuration 1s2 2s2 2p2p2p2                   Element - Neon

With total 10 electrons, and octet configuration (8 electron's in valence shell), this is a nobel gas configuration. The atomic number 10 matches with Neon.

---

Configuration [Ar] 4s2                    Element - Calcium

[Ar] has electronic configuration 1s2 2s2 2p6 3s2 3p6. So total electrons here is 18 + 2 = 20 electrons. With total 20 electrons, and 4s2 valence shell confguration, it belongs to the alkaline earth metal series. The element is Calcium.

---

Configuration [Ar] 3d22d2d2 4s2                    Element - Manganese

[Ar] has electronic configuration 1s2 2s2 2p6 3s2 3p6. With outer electronic configuration 3d5 4s2 and total electron count = 25, the element here is manganese.