Practice for atoms, half-life, and bonding

Sodium-24 has a half-life of 24 hours. How much Sodium-24 will remain in an 100g sample after 48 hours?

• 10.0 g
• 25 g
• 100 g
• 50 g

An atom of silicon has 14 protons, 16 neutrons, and 14 electrons, what is correct name for this atom of oxygen?

• Silicon-14
• Silicon-16
• Silicon-28.09
• Silicon-30

Elements that are semiconductors and are brittle solids, and are poor conductors at room temperature are ____.

• metals
• nonmetals
• metalloids
• Isotopes

Why elements in the group 18 such as Neon (Ne) are difficult to form compounds?

• It is a rare gas and hard to obtain
• Neon needs 6 more electrons fill its outermost energy level.
• Neon already has 8 Valence electrons in its outermost shell (full and stable)
• Neon need to lose one electrons so it can have 8

What is the name of the following compound? NaCl

• Aluminum chlordie
• Magnesium chloride
• Potassium chloride
• Sodium chloride

What is the formula for the covalent bond : dioxygen decachloride?

• O2Cl2
• O2Cl10
• OCl2
• O2Cl9

Which of the following is an advantage of nuclear power plants?

• More efficient greener and less pollutants
• The costs are low.
• No accidents happen
• Wastes are not radioactive.

A sample of element X decays to 1/16 of its original amount after 80 years. What is element X’s half-life?

• 80 Years
• 40 Years
• 20 Years
• 10 Year

The process in which light nuclei combine at extremely high temperatures, forming heavier nuclei and releasing energy.

• Fission
• Chain Reaction
• Half-life
• Fusion

Why is Hydrogen grouped with the alkali metals even though it is a gas?

• It has 1 proton
• It has 1 valence electron
• It is a metal
• It is a metalloid