Atom and Periodic Table Trends Quiz

Across Period 3, which property generally decreases?

• atomic radius

• electronegativity

• number of protons

• ionic charge

Which Period 3 element forms a +2 ion most readily?

• Phosphorus (P)
• Silicon (Si)
• Aluminum (Al)
• Magnesium (Mg)

Click on the metalloid in Period 3.

• Sodium
• Chlorine
• Silicon
• Argon

Why is Cl-35 not exactly 35 u in relative atomic mass?

• Cl-35 has a different number of neutrons than protons.
• Cl-35 is the only isotope of chlorine that exists.
• Cl-35 is not exactly 35 u because relative atomic mass is an average of isotopes, influenced by their natural abundances.
• Cl-35 is a synthetic isotope created in a lab.

Choose the correct isotope notation for sodium-24.

• 24Na+
• 24Na
• Na-24
• Sodium-24

Which real-world use matches C-14?

• smoke detectors

• dating fossils

• thyroid scans

• sterilising food

Several isotopes of cobalt are listed below. Select every isotope that is radioactive and widely used in medicine.

• Cobalt-58
• Cobalt-57

• Cobalt-59

• Cobalt-60

Which Period 3 element listed below has the highest first-ionisation energy?

• Phosphorus (P)
• Silicon (Si)
• Sodium (Na)
• Argon (Ar)

Why does the reactivity of the Group II metals (Mg → Ba) increase down the group?

• The reactivity of Group II metals increases down the group due to decreasing ionization energy and increasing atomic size.
• Group II metals become less reactive due to increased electronegativity.
• Atomic size decreases down the group, reducing reactivity.
• Reactivity decreases due to increasing ionization energy.

Moving down Group VII, reactivity…

• fluctuates
• remains constant
• decreases
• increases