Question

section 1 - electron configurations
(4 points each) use noble gas notation for the electron configurations.

1. element: carbon (c)

class:
electrons: 6
valence electrons:
electron configuration:

1. element: copper (cu)

class:
electrons: 29
valence electrons:
electron configuration:

1. element: iodine (i)

class:
electrons: 53
valence electrons:
electron configuration:

1. element: lead (pb)

class:
electrons: 82
valence electrons:
electron configuration:

Explanation:

Step1: Recall noble - gas notation rules

Noble - gas notation uses the electron configuration of the nearest noble gas with a lower atomic number as a starting point.

Step2: Find electron configuration for Carbon (C)

The nearest noble gas to carbon with a lower atomic number is helium (He). Carbon has 6 electrons. Helium has 2 electrons. So the electron configuration of carbon in noble - gas notation is $[He]2s^{2}2p^{2}$. It is a non - metal. It has 4 valence electrons.

Step3: Find electron configuration for Copper (Cu)

The nearest noble gas to copper with a lower atomic number is argon (Ar). Copper has 29 electrons. Argon has 18 electrons. The electron configuration of copper is $[Ar]3d^{10}4s^{1}$ (due to the stability of the full d - subshell). It is a transition metal. It has 1 valence electron.

Step4: Find electron configuration for Iodine (I)

The nearest noble gas to iodine with a lower atomic number is krypton (Kr). Iodine has 53 electrons. Krypton has 36 electrons. The electron configuration of iodine is $[Kr]4d^{10}5s^{2}5p^{5}$. It is a halogen. It has 7 valence electrons.

Step5: Find electron configuration for Lead (Pb)

The nearest noble gas to lead with a lower atomic number is xenon (Xe). Lead has 82 electrons. Xenon has 54 electrons. The electron configuration of lead is $[Xe]4f^{14}5d^{10}6s^{2}6p^{2}$. It is a post - transition metal. It has 4 valence electrons.

Answer:

1. Class: Non - metal; Valence Electrons: 4; Electron Configuration: $[He]2s^{2}2p^{2}$
2. Class: Halogen; Valence Electrons: 7; Electron Configuration: $[Kr]4d^{10}5s^{2}5p^{5}$
3. Class: Transition metal; Valence Electrons: 1; Electron Configuration: $[Ar]3d^{10}4s^{1}$
4. Class: Post - transition metal; Valence Electrons: 4; Electron Configuration: $[Xe]4f^{14}5d^{10}6s^{2}6p^{2}$