Atoms, Elements, Periodic Table S8P1a: Distinguish between atoms and molecules S8P1f: Recognize that there are more than 100 elements and some have similar properties as shown on the Periodic Table of Elements S8P1g. Identify and demonstrate the Law of Conservation of Matter

Elements

down into simpler substances by physical or chemical means. An element is a pure substance that cannot be broken down into simpler substances by physical or chemical means. Elements are the ingredients that make up everything that exists

2) A pure substance is one that has only one type of particle. Elements are pure because each atom with the same atomic number (same number of protons) belongs to the same element.

3) One particle (or piece) of an element is called an atom. All atoms with the same number of protons (atomic number) belong to the same element.

4) Elements can be identified by properties that don’t change no matter the size of the substance things like: boiling point, melting point, density and reactivity – these are the characteristic properties

Atoms are made of elements right Atoms are made of elements right? Turn to your neighbor to defend why or why not… 30 seconds…. GOOOO!!! Atoms Elements

An atom is the smallest part of an element that still has the properties of that element. (the smallest part of “stuff” that is still “stuff”)

2) Particles that make up an atom: a) protons: positively charged (+1) b) Electrons: negatively charged (-1) c) Neutrons: NO charge (+1 -1 = 0) Two hydrogen atoms are walking along the street. One suddenly goes: - Oh shoot, I´ve lost an ' electron! Other one says: -Are you sure? – Yes, he replies.- -I'm positive.

b) Electrons circle the nucleus in the electron cloud 3) Protons and neutrons are gathered together in the center of the atom called the nucleus b) Electrons circle the nucleus in the electron cloud Electron cloud nucleus

-this is called the atomic number 4) Atoms differ from one another because of the number of protons in the nucleus. -this is called the atomic number (all atoms with the SAME atomic number belong to the same element)

Tell me . . . 1) What are the three particles that make up an atom? 2) What is the center of an atom called? 3) What makes one type of atom different from another?

Periodic Table

Periodic Table of Elements 1) Elements are organized on the Periodic Table of Elements by atomic number.

2a) Periodic Table -columns are called groups or families because elements in a group behave alike or have similar properties

2b) Periodic Table – cont: Rows are called periods: Elements show a gradual change in properties across a period.                                                                                                                                                                            

3) Elements can be divided into three types: metals, nonmetals, and metalloids; these categories are based on how the element behaves.

gold, silver, iron, sodium, calcium location on table: left and middle 3a) Metals: properties: shiny, good conductors, ductile, malleable examples: gold, silver, iron, sodium, calcium location on table: left and middle Have students come up with properties – these should include: shiny, good conductors, ductile, malleable

dull/not shiny, not malleable, not ductile, poor conductors, brittle 3b) non-metals: properties: dull/not shiny, not malleable, not ductile, poor conductors, brittle examples: carbon sulfur oxygen location on table: far right Have students come up with properties: should include dull/not shiny, not mallable, not ductile, poor conductors, brittle

3c) metalloids: properties: moderate conductors – also called semiconductors properties of both metals and nonmetals examples: Silicon location on table: on the “Stair-step” line on the right

4) If you know the category, you know the properties, and for an unknown element, if you know the properties you can figure out the category.

Name the three categories of elements found on the Periodic Table. How are periods and groups on the Periodic Table different?