Do Now Get out your homework: Page 8 practice # 1 Page 9 practice #5 2. Check page 10 practice #6 Look at the back of the textbook.

Answers Page 8 practice # 1 Protons are found in the nucleus and have a positive charge. The # of protons is the same as the atomic number. Neutrons are found inside the nucleus and have no charge. They add mass to the atom. Electrons are found surrounding the nucleus and have a negative charge. They play a role in bonding.

Answers Pg. 9 # 5 4e- 2e- a) Carbon 6p+ 6no 1e- 1p+ b) Hydrogen 0no c) Aluminium

Answers Pg. 9 # 5 1e- 2e- d) lithium 3p+ 4no 1e- 8e- 2e- e) sodium f) fluorine 7e- 2e- 9p+ 10no

Answers Pg. 9 # 5 Pg. 10 #6 is in the back of the textbook 8e- 2e- 10no g) neon 2e- 2p+ 2no h) helium Pg. 10 #6 is in the back of the textbook

A1.1 The Structure of Matter

The Plan Go over pg. 5 & 6 of work booklet. Review valence electrons, Bohr & Lewis dot diagrams. A1.2 Atomic bonding and properties Work on summative assignment.

A1.2 Atomic Bonding & Properties Science 20 Unit A

Review-Valence Electrons An electron that occupies the outermost energy level in an atom. It is these electrons that determine the chemical properties of an atom. Atoms of different elements that have similar electron arrangements have similar characteristics and are arranged in families. All atoms strive to complete the outer shell with electrons and thus become a stable atom. They can complete these outer shells by gaining, losing or sharing electrons from other atoms.

Metals vs. Non-Metals Metals tend to form positively-charged ions (cations) Non-metals tend to form negatively-charged ions (anions)

Aluminum Is a metal that has luster, good heat and electrical conductivity, is malleable and ductile and tends to form positive ions. A non-metal is not flexible, does not conduct well and tends to form negative ions.

Rock Salt Is a compound which is made up of elements (sodium & chlorine). If one element is a metal & the other is a non-metal then the compound is called an ionic compound and the bond between a positive & a negative ion is called an ionic bond.

Metals + Non-Metals = ionic bonds

Sharing Electrons Two or more non-metallic atoms tend to share electrons to complete the outer shell. By sharing they form covalent bonds.

Plastics Composed of hydrogen & carbon, which are both non-metals. If two non-metals combine they form molecular compounds. The bonding does not involve ions, rather a sharing of electrons and the bond is called a covalent bond. The resulting compound is called a molecule.

Covalent Bonds Nonmetal + Nonmetal = covalent bonds

In General Bonds formed by molecular compounds are weaker than ionic compounds. The properties of the categories of matter, on pg. 21 of your text, can explain: Why molecular compounds will melt quicker than ionic compounds Why ionic crystals will snap if you try bending them, while molecular compounds will bend Why metals conduct better Why molecular compounds can dissolve

Assignment Practice problems #2, 3, & 9 (p. 14) Read pgs. 15-23 1.2 Questions: Pg. 23-24 #1-5 Diagrams of Atoms Summative Assignment–Due Monday, February 8th. Skip pg. 6 of notebook?