1.7 Periodic Trends

Mendeleev left spaces in his periodic table and predicted several elements and their

• atomic numbers.
• properties.
• colors.
• radioactivity.

Looking at atoms in the same valence energy level, what factor affects Coulombic attraction?

• distance from the nucleus
• number of protons

As the Coulombic attraction increases the atomic radius: increases or decreases?

• increases
• decreases

Which element has the smaller atomic radius: potassium (K) or bromine (Br)?

• potassium (K)
• bromine (Br)

As the Coulombic attraction in an atom increases, the energy needed to remove an electron: increases or decreases?

• decreases
• increases

Which element has the greatest ionization energy: Aluminum (Al) or Chlorine (Cl)?

• Chlorine (Cl)
• Aluminum (Al)

Which element has the greatest electronegativity: Nitrogen (N) or Arsenic (As)?

• Arsenic (As)
• Nitrogen (N)

The atom with the largest atomic radius in Group 18 is -

• He
• Rn
• Ar
• Kr

Alkali metals must be stored under oil because of their extreme

• Radioactivity
• Reactivity
• Softness
• Brilliance

The group of soft, silvery active metals, all of which have one electron in an s orbital, is known as the

• alkaline-earth metals.
• alkali metals.
• transition metals.
• metalloids.