Science Chapter B1 Classifying Matter

Lesson 1: What are Elements? Text pages B8-B15

Vocabulary element: periodic table: atom: nucleus: proton: neutron: electron: a substance that cannot be broken down into other substances by heat, light, or electricity a chart that classifies elements by their properties the smallest particle of an element that has the properties of the element the center of an atom, where protons and neutrons are located particle in an atom that has a positive electrical charge particle in an atom that has no charge particle in an atom that has a negative electrical charge

Building Blocks of Matter mattermatter = anything that has mass and takes up space Everything in the world is made up of matter. Matter is made up of 112 substances called elements. elementelement = a substance that cannot be broken down into another substance by heat, light, or electricity aluminum, gold, iron, etc. Elements combine to make different kinds of matter like letters combine to make different words.

A History Lesson Some ancient people thought all things in nature were made up of only four substances. earthearth airair waterwater firefire Early scientists began to recognize some elements for what they were, and began trying to identify all the elements. Substances were tested to see if they could be broken down. A French scientist, named Antoine-Laurent Lavoisier, completed the first list of elements. 60 elements

Properties of Elements Different elements have different properties.Different elements have different properties. MetalsMetals ShinyShiny Conduct heat and electricityConduct heat and electricity Can be hammered or pulled into shapesCan be hammered or pulled into shapes NonmetalsNonmetals Not shinyNot shiny Do not conduct heat and electricityDo not conduct heat and electricity Cannot be hammered or pulled into shapesCannot be hammered or pulled into shapes Gold, copper, silver, iron, etc.Gold, copper, silver, iron, etc. Oxygen, nitrogen, carbon, etc.Oxygen, nitrogen, carbon, etc.

The Periodic Table Scientists tried many different ways to group the elements. Dmitri Mendeleev (a Russian scientist) found a way. Elements numbered from lightest to heaviest Elements grouped by properties Elements placed in rows and columns (chart) Mendeleev saw a pattern. Mendeleev’s chart had holes in it that were later filled by newly-discovered elements. Periodic Table of ElementsPeriodic Table of Elements

The Periodic Table Each box on the periodic table contains special information about one element. Au 79 Gold Atomic number Elements are numbered from lightest to heaviest. The numbers run from Elements are numbered from lightest to heaviest. The numbers run from Symbol Each element has a symbol that stands for its name. “Au” are the first two letters of aurum, the Latin word for gold.Each element has a symbol that stands for its name. “Au” are the first two letters of aurum, the Latin word for gold. Name Element’s name are often listed.Element’s name are often listed.

The Periodic Table On the periodic table, elements are grouped in columns. Each column contains elements that have similar properties. They may look or act similarly. Most metals are grouped together. The same goes for nonmetals and man-made elements. H 1 Hydrogen Md 101 Mendelevium Rn 86 Radon Sn 50 Tin Fe 26 Iron

Atoms atomatom = a tiny particle of matter; the smallest particle of an element that has the properties of the element Atoms contain even smaller particles. nucleusThe center of an atom is called the nucleus. protonsprotons = positively charged particles found in the nucleus of an atom neutronsneutrons = particles found in the center of an atom that have no charge electronselectrons = negatively charged particles that move around outside the nucleus of an atom

Atoms Each atom has a certain number of protons, neutrons, and electrons. The atomic number tells both the number of protons and the number of electrons. Au 79 Gold Atomic number The atomic number of gold is 79. That tells us gold has 79 protons. Since the number of electrons is the same as the number of protons, we know gold has 79 electrons.The atomic number of gold is 79. That tells us gold has 79 protons. Since the number of electrons is the same as the number of protons, we know gold has 79 electrons. The number of neutrons can be different from one atom to another.

K 19 Potassium What is this element’s symbol? What is the name of this element? What is this element’s atomic number? How many protons does this element have? How many electrons does this element have?

Any Questions?