Structure of the Atom Section 4 2 Subatomic

Structure of the Atom (Section 4. 2)

Subatomic Particles G Light up your old tv screen G When the beam sweeps across your screen it lights up spots G There are three beams, one for each primary color of light G Red G Green G Blue G Particles in the beams are

Properties of Subatomic Particles G Protons, electrons, and neutrons are subatomic particles G Protons - a positively charged subatomic particle that is found in the nucleus of an atom G Charge is +1, Mass = 1 G Electrons - a negatively charged subatomic particle that is found in the space outside the nucleus G Charge is -1, mass = 1/2000 G Greek word means amber G Neutrons - a neutral subatomic particle that is found in the nucleus of an atom, no charge G Mass is almost exactly equal to that of a proton (mass = 1)

Comparing Subatomic Particles G Protons, electrons, and neutrons can be distinguished by mass, charge, and location in an atom G Protons and neutrons have almost the same mass G Protons have a positive charge G Neutrons have no charge

Comparing Subatomic Particles G Electrons have a mass about 2000 times smaller than that of a proton G But its charge is equal in size to and opposite of the charge of a proton G Found in the space outside the nucleus

Atomic Number G The atomic number of an element equals the number of protons in an atom of that element G Atoms of different elements have different numbers of protons G Can be used to refer to different elements G Atomic number is also the

Mass Number G Mass number - The sum of the protons and neutrons in the nucleus of an atom G Mass # = # protons + # neutrons G To find the number of neutrons in an atom subtract the atomic number from the mass number G # neutrons = mass # - Atomic #

Isotopes G Isotopes - atoms of the same element that have different numbers of neutrons and therefore different mass numbers G Isotopes of an element have the same atomic number but different mass numbers because they have different numbers of neutrons G Every atom of oxygen has 8 protons but some atoms have 8 or 9 or even 10 neutrons G Atoms with 8 have a mass number of 16 G Atoms with 9 have a mass number of 17 G Atoms with 10 have a mass number of 18

Isotopes G With most elements it is hard to notice any differences in the physical or chemical properties between the isotopes G Hydrogen-1 only has 1 proton and no neutrons G Hydrogen-2 has 1 proton and 1 neutron which doubles its mass, water that contains hydrogen 2 is called heavy water