Chemistry placement exam

Atomic Number - correct answer-The number of protons in the nucleus of an atom. The atomic number of an element never changes, meaning that the number of protons in the nucleus of every atom in an element is always the same. Hydrogen = 1, Carbon = 6, Oxygen = 8 (located on top of element of periodic table) Mass Number - correct answer-# of neurons + # of protons = mass number (located on bottom of periodic table) Isotopes - correct answer-Let's say an atom is missing a neutron or has an extra neutron. That type of atom is called an isotope. An atom is still the same element if it is missing an electron. Example: (carbon-14) Distribution B/W subatomic particles in an Atom - correct answer-A typical atom consists of three subatomic particles: Protons, Neutrons, and Electrons. - Nucleons include protons and neutrons. All the positive charge of an atom is contained in the nucleus, and originates from the protons. Neutrons are neutrally-charged. Electrons, which are negatively-charged, are located outside of the nucleus. Roles of subatomic particles: Protons, Neutrons, & Electrons - correct answer-Particle Mass: Protons & Neutrons have about same mass. Electrons have much less mass than protons and neutrons. Particle Charge: Protons have a positive charge (+)