Presentation on theme: "Ions and Isotopes Objective Students will be able to: use atomic symbols to represent different atoms and their isotopes. Identify and define ions of different."— Presentation transcript:
Ions and Isotopes Objective Students will be able to: use atomic symbols to represent different atoms and their isotopes. Identify and define ions of different elements
Some definitions Ion - an atom that has a positive or negative charge How does something have a positive or negative charge? Number of protons and electrons has to be different!
How can an atom become an ion? By gaining or losing electrons Losing Electrons= CATION Gaining Electrons= ANION
Cation Positive charge Formed by the atom losing electrons A neutral atom of sodium loses an electron and becomes Na +1 How many electrons does Li +1 have? Mg +2 ?
Anion Negative charge Formed by the atom gaining electrons Chlorine gains one electron and becomes Cl -1 How many electrons does Br -2 have? F -1 ??
Why do atoms become ions? Atoms want to have a full outer shell (orbital) –one electron in outer shell will lose the electron. –all but one electron will gain one. Which is likely to become a cation? Which is likely to become an anion?
Summary of Ions Lose electrons- become positive, which is a cation Gain electrons- become negative, which is an anion Electrons are gained or lost in the outermost shell These are called valence electrons
Atomic Notation Mass number= protons + neutron Atomic number= Protons Element Symbol P= N= E= 20 P= N= E= 777777
Isotopes Isotopes are atoms of the same element that have different numbers of neutrons. The mass number of an isotope tells you the number of protons plus the number of neutrons. Difference? Similarities? H-1 H-2H-3 http://web.visionlearning.com/custom/chemistry /animations/CHE1.3-an-isotopes.shtml
Learning Check Naturally occurring carbon consists of three isotopes, 12 C, 13 C, and 14 C. State the number of protons, neutrons, and electrons in each of these carbon atoms. 12 C 13 C 14 C 6 6 6 #p _______ _______ _______ #n _______ _______ _______ #e _______ _______ _______
Solution 12 C 13 C 14 C 6 6 6 #p 6 6 6 #n 6 7 8 #e 6 6 6
Heavy Water Application of isotope Duterium- 2 1 H can bind with oxygen Only occurs 1 in every 3200 molecules Concentrated heavy water is used for development of nuclear weapons Can be poisonous to plants and animals.
Cobalt-60 Application of isotope Has one extra neutron in the nucleus – Radioactive and emits gamma radiation, which can pass through materials easily – Sterilizes medical equipment and kills harmful bacteria