Which of the following illustrates the Quantum Mechanical Model of an Atom?

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“You cannot tell the exact location of an electron, how exactly it is moving, even the exact energy it carries”. What do you call this principle?

• Aufbau Principle

• Pauli Exclusion Principle

• Hund’s Rule

• Heisenberg’s Uncertainty Principle

What is the correct electron configuration of a Chlorine atom?

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Which of the following sets of quantum numbers IS ALLOWED?

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An atom has an electron configuration of 1𝑠 2 2𝑠 2 2𝑝 5 . How many valence electrons does this atom have?

• 1

• 3

• 5

• 7