The Science of Chemistry Atom and the Periodic Table 1 Atoms • Atoms are very small particles that surround us and make up everything considered “matter” • The size of an atom is about 10 -8 cm (0.00000001cm) • There are 3 important parts of an atom: • Electrons – Negative charge (e - ) • Neutrons – Neutral charge (n) • Protons – Positive Charge (p + ) 2 The Theory of Matter • “Matter” is anything that has mass and takes up space. • Mass: a measure of the amount of substance in an object. • Volume: a measure of how much space an object occupies. 3 The Theory of Matter • Four “States of Matter”: • Solid • Liquid • Gas • Plasma * or a combination of materials in one or more states eg. foam (liquid/gas or solid/gas) 4
Transcript
The Science of Chemistry
Atom and the Periodic Table
1
Atoms• Atoms are very small particles that surround
us and make up everything considered “matter”
• The size of an atom is about 10-8 cm (0.00000001cm)
• There are 3 important parts of an atom: • Electrons – Negative charge (e-) • Neutrons – Neutral charge (n) • Protons – Positive Charge (p+)
2
The Theory of Matter• “Matter” is anything that has mass
and takes up space. • Mass: a measure of the amount of
substance in an object. • Volume: a measure of how much
space an object occupies.
3
The Theory of Matter• Four “States of Matter”:
• Solid • Liquid • Gas • Plasma
* or a combination of materials in one or more states eg. foam (liquid/gas or solid/gas)
4
Question• What are two features that are common to
all forms of matter?
MASS and VOLUME
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The Theory of Matter• All matter is made up of tiny particles. • Particles attract each other. • Particles are always moving. • Each substance has its own kind of
particle. • Particles move at different speeds.
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Classifying Matter• Matter is classified - put into
categories - based on characteristics or properties.
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Classifying Matter
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Question• How is a mechanical mixture different
from a solution?
Different substances within are visible.
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Review Questions1. What are the three parts of an atom? 2. What are the four states of matter? 3. What two features are common to all
forms of matter? 4. Re-state the five statements in the Theory
of Matter. 5. Compare a heterogeneous mixture to a
homogeneous mixture.
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Properties of Matter• Matter exists with properties that are either
considered PHYSICAL or CHEMICAL. • A physical property describes a
characteristic of a substance that is observable without a change in it’s composition.
• A chemical property describes a characteristic of a substance when it reacts to form a new substance or new substances.
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Physical Properties of Matter
• Every substance has its own set of physical properties.
• Consider water…. • sticks to itself (cohesion). • sticks to other substances (adhesion). • liquid at room temperature. • expands and loses density when
frozen; floats on water.
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Chemical Properties of Matter
• Every substance has its own set of chemical properties.
• Due to a chemical property referring to a change that can take place, it is called a chemical change.
• A chemical change always results in the formation of a new substance or substances with different properties.
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AssignmentPART A: Using your assigned Physical Property of Matter, create a Pechakucha PowerPoint. PART B: Present your Pechakucha to the class. PART C: Fill in a Table comparing the Physical Properties of Matter.
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Summary of Physical and Chemical Properties of Matter
• PHYSICAL properties are observed with senses and determined without destroying matter.
• CHEMICAL properties indicate how a substance reacts with something else and how matter is changed into a new substance after the reaction.
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Summary of Physical and Chemical Properties of Matter
Worksheet • Use the textbook (Chapter 4) and
your notes to find answers. • Work with your group to find the
answers to the questions.
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Changes within Matter• Matter can change shape or
turn into a new substance. • Changes in matter can be
classified in 2 groups: • Physical Change • Chemical Change
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Physical Change• Substance and the original
properties are changed. • The particles stay the same. • Usually changes in shape and
size. • EXAMPLE – Ice melting
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Chemical Change
• Substance and the original properties are changed.
• The particles stay the same, but you cannot get the original substance back.
• EXAMPLE – Water + Salt
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Indicators of Chemical Change
• Change in color • Heat is produced or absorbed
• Light is given off
• Grains of solid form in a liquid • Production of a new substance
• Changes in properties of original substance
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Classifying Matter Review
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Elements–An element is a pure substance and an atom. –Elements cannot be broken down into smaller
particles. –Elements are organized in a particular sequence.
• Nucleus: of protons and neutrons
• Electron shells: with specific numbers of electrons around the nucleus.
–Each element has a different property.
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Elements
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ElementsElement Name: The full name of element. Element Symbol: The letter or letters that represent the element. Atomic Number: The number of protons. Atomic Mass: The number of protons + number of neutrons.
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Rules for Element Symbols
• Each element is given a symbol. • Some of the names of elements are derived
from “Latin” or simply from the name of the scientist who discovered it.
• The symbol always begins with a capital letter.
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Electron Locations
• Electrons are found in the area surrounding the nucleus in electron shells.
• Each shell has a specific number of electrons.
• Each shell has a name (K, L, M, N, O, P).
• Each shell represents a level of energy of the atom.
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Electron ShellsEnergy Level Shell # of
Electrons1 K 2
2 L 8
3 M 8
4 N 18
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Bohr Diagram• A Bohr Diagram shows
how electrons are located in an element.
• Key Points:
• Electrons are put into four regions of each shell.
