Lesson 2 Subatomic particlesAtom: the smallest particle of an elementSubatomic Particles
Atoms are made up of three particles: particle charge mass location proton (p) + 1 amu (u) nucleus neutron (n) no charge 1 amu (u) nucleus electron (e) - 1/1836 amu (u) orbital amu: atomic mass unit - 1/12 the mass of a carbon atom Nucleus: the dense positively charged central core of the atom Orbital: a region in the atom where there is a high probability of locating an electron. Atomic Number: number of protons in the nucleus (Bottom # on PT) *identifies the element (like your SS#) Mass number: total number of protons and neutrons in the nucleus (Top # on PT) Nuclear Charge: (always +) equals atomic number (neutrons have no charge) Isotopes: elements that have the same #p, but different #n (same element but different masses) atomic mass: the average mass of all of the isotopes of an element Net (overall) charge = #p - #e All elements, as written, on the periodic table are neutral. This means that #p = #e ***If an atom does not have the same number of protons and electrons it is an ION and is positive (if it has more protons) or negative (if it has more electrons).
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