Chemists can identify the composition of some unknown salts by conducting a flame test. When potassium salts are heated in a flame, a purple color is observed.

This is due to the movement of electrons between energy levels. What is the electron configuration of a potassium atom at ground state?

• 1s²; 2s²; 2p⁶; 3s²; 3p⁶; 4d¹

• 1s²; 2s²; 2p⁶; 3s²;3p⁶; 3d¹

• 1s²; 2s²; 2d⁶; 3s²; 3d⁶; 4s¹

• 1s²; 2s²; 2p⁶; 3s²; 3p⁶; 4s¹

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The electron configuration of an atom is 1s²2s²2p⁶.  The number of electrons in the atom is 

• 3
• 6
• 8
• 10

What atom matches this electron configuration?
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰

• Zinc
• Copper
• Nickel
• Germanium

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What electron configuration matches an oxygen atom?

• 1s²2s²2p⁶3s2, 3p⁶4s²3d¹⁰4p⁵
• 1s²2s²2p⁴
• 1s²2s²2p⁶
• 1s²2s²2p⁶3s²3p⁶4s²3d¹

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An orbital can at most hold how many electrons?

• 1 electron
• 2 electrons
• 3 electrons
• 4 electrons

The electron configuration of an atom is 1s²2s²2p⁶.  The number of valence electrons in the atom is 

• 3
• 6
• 8
• 10

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What is the electron configuration for this atom?

• 1s²2s²2p⁶
• 1s²2s²2p⁵
• 1s²2s²2p³
• 2s²2p³

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Which element has 2,8,8 electrons per shell?

• Lead

• Fluorine

• Neon

• Argon

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How many electrons does Si contain? (click to see image)

• 14
• 28
• 2
• 4

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How many valence electrons does Si contain? (click to see image)

• 14
• 28
• 2
• 4

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