2. Atoms & Elements

Which of the following is the atomic number of krypton (Kr)?

What is the atomic number of the element silicon (Si)?

Which of the following best describes what a chemical symbol represents on the periodic table?

How many elements are currently recognized on the modern periodic table?

Which of the following is the atomic number of carbon?

Which of the following is the chemical symbol for potassium?

Which term is used to describe the horizontal rows on the periodic table?

Which element on the periodic table has 78 protons?

Which of the following element symbols represents the element with atomic number 12 among the first 20 elements of the periodic table?

What is the atomic number of chlorine?

Which of the following pairs correctly matches an element with its chemical symbol?

3. Sodium (Na) is found in which period of the periodic table?

How many elements are currently represented on the periodic table of elements?

Which neutral element has 89 electrons?

Who is usually recognized for creating the modern periodic table?