2. Atoms & Elements

Which of the following is considered the basic unit of chemistry?

Which of the following best explains why hydrogen and helium are the two most common elements in the universe?

Which term describes a chemical substance that cannot be broken down into simpler substances by chemical means?

Which type of scientist primarily studies matter and its composition?

Which element has more electrons in a neutral atom: hydrogen or uranium?

An electron and a proton are fixed at a separation distance of 1.0 nm. What is the magnitude of the electrostatic force between them?

Where is most of the mass of an atom located?

Which feature defines a neutral atom?

Which of the following is the number of protons in a lead (Pb) atom?

Which of the following best describes the structure of an atom?

Which subatomic particle is found in the nucleus of an atom and has a positive charge?

Which of the following is the number of protons found in an atom of iodine?

Which of the following correctly identifies the subatomic particles found in the nucleus of a nitrogen atom?

What is the total number of individual atoms present in a single molecule of water (H_2O)?

Which element corresponds to an atom that has 29 protons?