AC-HPAT Prep: Chemistry | 50 Actual Questions and Answers 100% Correct| Latest Update

What is an atom? ✔✔An atom is the basic unit of an element. It is composed of a nucleus and one
or more electrons moving around it.
What is an electron? ✔✔A negatively charged subatomic particle.
What is a proton? ✔✔a stable subatomic particle occurring in all atomic nuclei, with a positive
electric charge equal in magnitude to that of an electron, but of opposite sign.
The number of protons in an atom indicates: ✔✔The atomic number.
What is the mass number? ✔✔The sum of protons and neutrons in the nucleus of the atom.
What is the atomic number? ✔✔The number of protons int the atom, specific for each element.
What is an isotope? ✔✔Atoms of the same element that have the same number of protons, but a
different number of neutrons. They have identical chemical properties, but different physical
properties.
What is the atomic mass? ✔✔The weighted average of an isotope's masses.
What is the mass number of an atom with 60 protons, 60 electrons, and 75 neutrons? ✔✔135
What is the atomic number of an atom with 17 protons, 17 electrons, and 20 neutrons? ✔✔17
An atom with an atomic number of 58 and an atomic mass of 118 has how many neutrons? ✔✔60
The mass of an atom is almost entirely contributed by its: ✔✔Nucleus
If an atom consists of 9 protons and 10 neutrons, it's number of electrons is: ✔✔9