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Electrical Nature of Matter. Grade Nine Science. Question to Ponder. What happens when you rub a balloon against your hair? Does this action create electric charges?. What happens when you rub the balloon against your hair?. Both items have negative and positive charges.
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Electrical Nature of Matter Grade Nine Science
Question to Ponder • What happens when you rub a balloon against your hair? • Does this action create electric charges?
What happens when you rub the balloon against your hair? • Both items have negative and positive charges. • In fact, both items are said to be neutral • Since the balloon and your hair are comprised of two different materials one item wants the negative charges more. • One item becomes positive, the other negative • Now each item is said to be charged.
Electrostatics: study of static electric charge. • Static electricity (When Charges DO NOT Move). • This is why the balloon can stick to the wall • This is a result of “The Law of Electric Charges”
The Law of Electric Charges • Like charges repel one another, and unlike charges attract one another. • How would you test for this? • Place a known charge to an object with an unknown charge
A Model for the Electrical Nature of Matter • The Bohr-Rutherford model helps us understand how matter is structured and how it behaves. • The main ideas of this model are presented on the next couple of slides.
A Model for the Electrical Nature of Matter • All matter is made up of particles called atoms. • At the centre of each atom is a nucleus, with two kinds of particles: the positively charged proton and the uncharged neutron. Protons do not move from the nucleus when an atom becomes charged.
A Model for the Electrical Nature of Matter • Negatively charged particles called electrons surrounds the nucleus. When atoms become charged, only the electrons move from atom to atom. • Like charges repel each other; unlike charges attract each other. • Some elements have a weaker attraction for its electrons than others and the electrons are able to move freely from atom to atom. A good example is copper
A Model for the Electrical Nature of Matter • A single atom is always electrically neutral. • If an atom gains an extra electron, the net charge on the atom is negative and it is called a negative ion. If an atom loses an electron, the net charge on the atom is positive and it is called a positive ion.
Negative Ions If an atom gains an extra e-, the net charge on the atom is negative , and it is called a negative ion . 6 protons (6+) 6+ 6 electrons (6-)7- Neutral 0 (no charge) 1- (-ion)
Positive Ions If an atom loses an extra e-, the net charge on the atom is positive , and it is called a positive ion . 6 protons (6+) 6+ 6 electrons (6-)4- Neutral 0 (no charge) 2+ (+ion)
Homework Page 273 – questions 1-5