Unit 1

1. Unit 1 Structure and Properties of Matter

2. Matter • Matter is defined as anything that has mass and takes up space. • There are 2 types of matter: • Pure substances (elements and compounds) • Mixtures

3. Pure Substances vs. Mixtures • If it is on the periodic table of the elements, it is an element. • If a substance has a chemical formula, then it is a compound, which is a pure substance. • A mixture is 2 or more pure substances together • Categorize the following as elements or compounds: • Carbon dioxide • Air • Apple juice • Gold • Arsenic

4. Atoms • Atoms are the basic building blocks of the universe. • Atoms are made up of 3 subatomic particles: • Protons: have a positive charge; located in the nucleus of an atom • Neutrons: have no charge; located in the nucleus • Electrons: have a negative charge; located outside the nucleus of an atom in energy levels

5. Elements and the Periodic Table • Elements are substances that are made up of atoms of the same type of atom • Vocab terms: • Atomic number: number of protons in the nucleus of an atom • Mass number: sum of protons and neutrons in the nucleus of an atom • In an atom, there are equal numbers of protons and electrons; therefore atoms are electrically neutral.

6. Element Squares on Periodic Table Atomic Number Element Symbol Element Name Average atomic mass

7. Classification of Elements • How are elements organized on the periodic table? • By order of increasing atomic number (number of protons) • Rows on the periodic table are called periods. • There are 7 Periods. • Columns on the periodic table are called groups or families. • There are 18 Groups.

8. Important Notes • Most of the mass of an atom is in the nucleus (protons and neutrons); electrons are so small their mass is considered negligible. • To calculate the number of neutrons in an atom, round the average atomic mass to the nearest whole number. Then, take mass number – atomic number.

9. Periodic Table • All elements on the periodic table fall into one of these 3 categories: • Metals • Nonmetals • Metalliods

10. Metals • Located on left side of Periodic Table (Hydrogen is the exception) • Metals are typically solids at room temperature (Mercury is the exception) • They are malleable: can be hammered into thin sheets • They are ductile: can be stretched into thin wires • Generally good conductors of heat and electricity.

11. Nonmetals • Located on the right hand side of the Periodic Table. • Are typically dull in appearance. • They are poor conductors of heat and electricity.

12. Metalloids (aka Semiconductors) • Metalloids are located along the stair-step line on the right side of the periodic table. • Metalloids have characteristics of both metals and nonmetals.

13. Valence Electrons • Valence electrons are electrons located in the outermost energy level of an atom. • All elements in the same group (family) have the same number of valence electrons. • # Valence Electrons • Group 1: 1 • Group 2: 2 • Group 13: 3 • Group 14: 4 • Group 15: 5 • Group 16: 6 • Group 17: 7 • Group 18: 8

14. Diagram of an atom • Draw a diagram on a sodium atom. • Draw a diagram of a chlorine atom.

15. Practice • Fill in the table below: