Periodic Table, Isotopes and Radioactive Decay Presented by Kesler Science
Essential Questions: 1. What is an isotope. 2. How are elements classified on the periodic table? 3. How do scientists measure the decay of isotopes?
Atom The basic unit of a chemical element. (ex: gold, oxygen, mercury) Consists of 3 basic parts. (protons (+), neutrons (0), electrons (-)) The atomic mass is the sum of the protons and neutrons.
Protons: Positively charged subatomic particle Found in the nucleus of an atom.
Neutrons: Subatomic particle with no charge Neutral Found in the nucleus of an atom
Electrons Negatively charged subatomic particle. Located outside the nucleus.
Periodic Table The periodic table arranges all of the known elements in order of increasing atomic number (# of protons). Order generally coincides with increasing atomic mass, too.
What can we tell about this element (atom) from the periodic table? 1. The atomic number(14), which is also the number of protons. 2. The symbol for silicon. (Si) 3. The atomic mass. (28.0086), which is the sum of the protons and neutrons. 4. The element s (atom s) name. (Silicon) 14 Si 28.0086 Silicon
Periodic Table Classification: Metals (blue) properties: Solid at room temperature (except mercury) Shiny luster Ductile (bend into a wire) Malleable (hammered) Good conductor (heat and electricity) High density High melting point Reactivity those metals at the bottom left corner of the PT are most reactive Metals, Nonmetals & Metalloids
Periodic Table Classification: Metals, Nonmetals & Metalloids Nonmetals (red) properties: No luster (dull appearance) Poor conductor of heat and electricity Brittle (breaks easily) Not ductile Not malleable Low density Low melting point Less reactive than metals
Periodic Table Classification: Metals, Nonmetals & Metalloids Metalloids (green) Elements on both sides of the zigzag line (staircase) have properties of both metals and nonmetals.
Quick Action Match the words with the definition With a partner match the classification with the object. 1. Metal 2. Nonmetal 3. Metalloid A. Shiny new Yeti cup B. Carbon in your pencil lead C. Yellow glob of sulfur D. Nitrogen in the air E. Silicon used in microprocessors in cell phones F. Helium in a balloon G. An aluminum can
Periods on the Periodic Table The periods on the PT are the rows numbered from 1-7. Atomic number increases from left to right. Chemical properties are not all similar.
Groups on the Periodic Table The groups or families on the PT are the columns numbered from 1-18. Chemical properties are very similar. Groups 1 is the most reactive and group 18 is the most inert (stable).
There can be more neutrons in the nucleus of an atom, this is called an isotope. It is still the same element, only there are a different amount of neutrons. The universe has a lot of carbon in the form of carbon-12 6 protons and 6 neutrons Carbon 14 is an isotope of carbon 6 protons and 8 neutrons
Radioactive Decay/ Half-Life Isotopes atoms are not stable and lose energy by emitting radiation The time it takes for the decay to occur is called a half-life A half-life is the time it takes the initial (parent) isotope to decay by half the initial amount. 1st - ½ or 50% of parent remaining 2nd ¼ or 25% of parent remaining 3rd - ⅛ or 12.5% of parent remaining etc.. This pattern continues until the parent is fully decayed.