chemistry

• What is the smallest unit of an element?

  atom
• How many elements are there in the periodic table?

  118
• Which element is a noble gas?

  Helium
• What is the atomic number of carbon?

  6
• Which gas is the most abundant in Earth's atmosphere?

  Nitrogen
• Which process converts a solid directly into a gas?

  Sublimation
• What does pH measure in a solution?

  Acidity
• What is the unit of measurement for the amount of a substance?

  mole
• Which gas is responsible for the greenhouse effect?

  Carbon Dioxide
• What is the chemical symbol for gold?

  Au