Question

rpcc chem 1010l: postlab - electron configuration
name glorious namazue 22109/25 section #

1. write out the electron configurations of each of the metals of the salt compounds used and of carbon. potassium is already done as an example for you. hint: the periodic table is very helpful and can be used as a guide.

element	electron configuration
sodium (na)	$1s^{2}2s^{2}2p^{6}3s^{1}$
potassium (k)	$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}$
calcium (ca)	$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}$
strontium (sr)
barium (ba)
carbon (c)

1. what is the approximate wavelength of light emitted from each of the salts?

substance	color	wavelength (nm)
sodium chloride (nacl)
potassium chloride (kcl)
calcium chloride ($cacl_{2}$)
strontium chloride ($srcl_{2}$)
activated charcoal (c)

1. why does a salt compound give off light or a colored flame?
2. did lithium and strontium emit similar colors? why or why not?

Explanation:

Step1: Recall electron - configuration rules

Use the Aufbau principle, Pauli - exclusion principle, and Hund's rule.

Step2: Determine electron configuration of Calcium (Ca)

Ca has 20 electrons. The electron configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}$.

Step3: Determine electron configuration of Strontium (Sr)

Sr has 38 electrons. The electron configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}$.

Step4: Determine electron configuration of Barium (Ba)

Ba has 56 electrons. The electron configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}$.

Step5: Determine electron configuration of Carbon (C)

C has 6 electrons. The electron configuration is $1s^{2}2s^{2}2p^{2}$.

Step6: Recall flame - test color and wavelength data

Lithium Chloride (LiCl) burns red - orange, approximately 670 - 680 nm.
Sodium Chloride (NaCl) burns yellow, approximately 589 nm.
Potassium Chloride (KCl) burns violet, approximately 766 nm.
Calcium Chloride ($CaCl_{2}$) burns orange - red, approximately 617 - 622 nm.
Strontium Chloride ($SrCl_{2}$) burns red, approximately 647 - 677 nm.
Activated Charcoal (C) does not typically produce a distinct colored flame in a simple flame test.

Step7: Explain salt - compound light emission

When a salt compound is heated, electrons in the metal atoms are excited to higher energy levels. When they return to their ground states, they emit light of specific wavelengths corresponding to the energy differences between the levels.

Step8: Compare lithium and strontium colors

Lithium and strontium do not emit exactly the same colors. Lithium has a red - orange color and strontium has a more intense red color. This is because the energy levels and electron transitions in their atoms are different, leading to different emitted wavelengths.

Answer:

Element Electron Configuration:
Calcium (Ca): $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}$
Strontium (Sr): $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}$
Barium (Ba): $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}$
Carbon (C): $1s^{2}2s^{2}2p^{2}$
Substance Color Wavelength (nm):
Lithium Chloride (LiCl) Red - orange 670 - 680
Sodium Chloride (NaCl) Yellow 589
Potassium Chloride (KCl) Violet 766
Calcium Chloride ($CaCl_{2}$) Orange - red 617 - 622
Strontium Chloride ($SrCl_{2}$) Red 647 - 677
Activated Charcoal (C) No distinct color N/A

1. When a salt compound is heated, electrons in metal atoms are excited and then emit light when returning to ground states.
2. Lithium and strontium do not emit similar colors because their electron transitions and energy levels are different.