Atomic Structure and Periodicity

Atoms of an element, X, have the electronic configuration 1s²2s²2p⁶3s²3p³ . The compound most likely formed with magnesium, Ca, is

• Ca₂X

• CaX₂

• CaX₃

• Ca₃X₂

The elements in which of the following have most nearly the same atomic radius?

• Ne, Ar, Kr, Xe

• Mg, Ca, Sr, Ba

• C, P, Se, I

• Cr, Mn, Fe, Co

Which shows an impossible electron configuration?

• 1s² 2s²2p⁶ 3s²3p⁶

• 1s² 2s²2p⁶2d¹⁰ 3s²3p⁶

• 1s² 2s²2p⁶ 3s²3p⁶3d⁵

• 1s² 2s²2p⁶ 3s²3p⁶3d³ 4s²

Which shows the ground–state configuration for the atoms of a transition element?

• 1s² 2s²2p⁶ 3s²3p⁶

• 1s² 2s²2p⁶2d¹⁰ 3s²3p⁶

• 1s² 2s²2p⁶ 3s²3p⁶3d⁵

• 1s² 2s²2p⁶ 3s²3p⁶3d³ 4s²

Which shows the ground–state configuration of a negative ion of a halogen?

• 1s² 2s²2p⁶ 3s²3p⁶

• 1s² 2s²2p⁶2d¹⁰ 3s²3p⁶

• 1s² 2s²2p⁶ 3s²3p⁶3d⁵

• 1s² 2s²2p⁶ 3s²3p⁶3d³ 4s²

Which of the following conclusions can be drawn from J. J. Thomson’s cathode ray experiments?

• Atoms contain electrons.

• Practically all the mass of an atom is contained in its nucleus.

• Atoms contain protons, neutrons, and electrons.

• Atoms have a positively charged nucleus surrounded by an electron cloud.

What is the most electronegative element?

• O

• Rb

• Mg

• N

Which of the elements above has the smallest ionic radius for its most commonly found ion?

• O

• Rb

• Mg

• N

Which of the following Indicates that an atomic orbital can hold no more than two electrons?

• Heisenberg Uncertainty Principle

• Pauli Exclusion Principle

• Hund’s Rule

• Shielding Effect

Which of the following predicts that it is impossible to determine simultaneously the exact position and the exact velocity of an electron?

• Heisenberg Uncertainty Principle

• Pauli Exclusion Principle

• Hund’s Rule

• Shielding Effect