Chapter 1 lesson 2

1. Chapter 1 lesson 2 What makes up matter? By Amelia

2. Atoms and Elements Atoms: an atom is the smallest particle of an element Atomic number: the number of protons in a nucleus is the elements atomic number Each element is made of one kind of atom, so elements are called pure substances

3. Molecules Molecule: a molecule is the smallest part of a substance made from more then one atom has still has the properties of a substance. Atoms can combine to make new molecules

4. Images of Molecules Atoms and molecules are too small to be seen-even under a microscope! Scientists have developed technology that allows them to make images of molecules. The first mention of the atom was about 2,500 years ago by a Greek philosopher named Democritus.

5. Elements and the Periodic Table The elements are arranged in order according to the atomic number. Elements with similar properties, such as metals, are grouped together. Elements in each column have similar chemical properties. Elements found in the last column on the right are gases at room temperature.

6. Classifying Elements Each element is made of one kind of atom. An element’s set of protons, neutrons, and electrons Metals are usually solid, are good conductors of heat and electricity, and can be made into wires and hammered into sheets. Non-Metals are usually brittle, poor conductors of heat and electricity, and cannot be hammered into sheets or made into wires. Metalloids are elements that have some properties of both metals and nonmetals.

7. Information on the Periodic Table • Each block in the Periodic Table contains information on each element: • Atomic Number • Chemical Symbol • Name of the Element • You can learn about its properties by looking at its location on the periodic table.

8. Groups and Periods • The periodic table has 18 columns. Each column is called a group or a family. • Elements in a group have similar properties. • Each row in the periodic table is called a period. • The first element in the row is very reactive and the last element is inactive.

9. Metals and Their Properties Shiny Malleable (can be bent and shaped without breaking) Conducts heat and electricity Ductile (can be pulled into wires)

10. Combining Metals Some metals are not pure elements. These are called alloys. Metals made from more than one element has many uses because it combines their properties. Brass is sturdier than copper and sturdier than zinc.