2. Atoms & Elements

Which of the following best describes the difference between an element and a molecule?

Atoms of a specific element always have a constant number of _____.

Chemists assign atoms to chemical elements by counting their:

How many silicon atoms are present in one molecule of SiH_4?

Which statement best describes how an atomic model can be used to explain the charge of the particles in Thomson's cathode ray beams?

Which type of atom is present in both water (H2O) molecules and carbon dioxide (CO2) molecules?

Which of the following is an example of an element?

Which of the following correctly lists the three main subatomic particles found in a typical atom?

An atom of calcium contains 20 protons. How many electrons does it have in its neutral state?

Which part of the atom is the space surrounding the nucleus that has an overall negative charge?

How does the size of oxygen’s nucleus affect the distribution of electrons in a water (H₂O) molecule?

Which element has atoms that contain exactly 11 protons?

Which of the following is the basic unit of a chemical element?

An atom has an atomic number of 15 and a mass number of 31. How many protons are present in this atom?

Which of the following statements about the molecule Be_2 is correct?