3 A ReviewElement – Chemical substance that cannot be divided by chemical meansAll atoms of the same element have the same atomic numberAtom – A small piece of matter made of a nucleus and electron cloud(s)Nucleus contains protons and neutronsNeutral atoms have equal numbers of protons and electrons
4 Review Continued Atomic Number – the number of protons in the nucleus. Mass Number – The total number of protons and neutrons in the nucleusIon – an atom that has lost or gained electronsIsotopes – atoms of the same element that have different numbers of neutrons
5 The New StuffRadiation – energy that is emitted from a source and travels through spaceMeasured with a Geiger CounterHave You Ever BeenExposed to Radiation?Is all radiation harmful?
6 More TermsNon-Ionizing Radiation – radiation that does not have enough energy to ionize matterIonizing Radiation – High-energy radiation which is capable of knocking electrons out of atomsNuclear Radiation – radiation produced from the nucleus of an atomRadioactive – unstable nucleus which spontaneously emits ionizing radiation
7 Types of Nuclear Radiation Alpha Particle – (α) helium ions that have no electrons and are positively chargedBeta Particle – (β) electrons emitted at very high speedGamma Ray – (γ) high energy radiation which has no mass or chargePositron – same mass as an electron but with a positive charge
9 Nuclear Decay Spontaneous Starts as a parent Becomes a daughter Gives off heat (energy)May continue as a series until a stable atom is formedMass Number and electric charge must be conserved during a nuclear change
14 Nuclear Power Uses fission to generate electricity Fission = The splitting of a large nucleus to produce smaller ones and energyBombardment with neutronsNeed critical mass that will sustain a chain reactionControlled in a reactorUncontrolled in an explosionFusion = The combining of small nuclei to form larger ones releasing energy
17 Synthetic Elements Transmutation – changing one element into another Carried out inNuclear ReactorsNuclear ExplosionsAcceleratorsTransuranium – synthetic elements with an atomic number greater than 92