Download Day 05- Matter and the Atom

Day 05­ Matter and the Atom
Minds On
Concept Attainment Activity
Action
The Atom, Isotopes, Radioisotopes
Average Atomic Mass
Standard Atomic notation
Consolidation
Std Atomic Notation WS (most finished)
AAM WS- homework
Matter and the Atom
By the end of today you shouldbe able to
• explain the relationshipbetween the atomic number andthe mass
number of an element
• distinguish between an isotopeand a radioisotope
• calculate average atomic mass of an element
Chemistry is the study of the composition, structure, properties and transformations of matter. Matter is defined as anything that takes up volume. Matter is classified based on what type of particles make it up.
Concept Attainment Activity
1. Cut out the pictures and sort them on your desk most complex ­­­­­­­­­> least complex
2. Arrange the pieces into the blank table in a way that makes sense to you.
3. What do these pictures represent? Add labels to the columns in your table.
Day 05­ Matter and the Atom
Matter
Mixtures
Pure Substances
one basic type of particle
Compounds
2 or more elements in the basic particle
Elements
more than one type of particle
1 element in the basic particle
Mixture
Solutions
only 1 visible substance or phase
Mechanical Mixtures
2 or more visible parts or phases
Pure Substance
Elements
Compounds
Day 05­ Matter and the Atom
The Nucleus: Crash Course Chemistry #1 (10 min) Awesome video!!
http://www.youtube.com/watch?v=FSyAehMdpyI
Atoms and Their Composition
• An atom is the smallest particle of any element that still retains the identity and properties of that element.
• Atoms are made up of even smaller subatomic particles called protons, neutrons, and electrons.
Which particles are located in the nucleus?
Which particles move around outside the nucleus?
What element is shown in the picture?
(Hint: also found in your pencil)
Day 05­ Matter and the Atom
Size of the Atom
The average size of the atom is 10­10 m in diameter. Subatomic particles are even smaller than that! To get an idea of just how tiny the atom is see.
http://micro.magnet.fsu.edu/primer/java/
scienceopticsu/powersof10/
Subatomic Particles
Element Builder Gizmo www.explorlearning.com
What causes the element to change? When is the atom ionized?
Atomic Number
The number of protons defines the type of atom. Every atom of helium contains 2 protons.
Every atom of sulfur contains 16 protons.
the # protons
Chemists use the term ATOMIC NUMBER (symbol Z) to refer to the number of protons in the nucleus of each atom.
Where can you find the atomic number for Aluminum?
How many protons does Aluminum have? Neutral Atoms
Neutral atoms do not have a + or ­ charge. For neutral atoms,
# protons = # electrons
so the atomic number also tells you the number of electrons in the atom, as long as the atom is neutral.
Day 05­ Matter and the Atom
Mass Number
Electrons are so tiny that their mass is almost 0, so
mass of an atom = (mass of protons + mass of neutrons)
Chemists use the term MASS NUMBER (symbol A)
to refer to the mass of an atom. How could you find the mass of neutrons in an atom if you know the atomic number and the mass number?
Subtract! MASS # ­ ATOMIC # = mass of neutrons
Isotopes
All atoms of the same element contain the same number of protons, but the number of neutrons can vary. For example, most of the oxygen atoms in nature have 8 neutrons in their atomic nuclei. Since all oxygen atoms have 8 protons, this means that most oxygen atoms have an atomic mass of 8+8 = 16. There are also two other stable forms of oxygen that occur in nature. One with 9 neutrons and an atomic mass of 8+9= 17, and one with 10 neutrons and an atomic mass of 8+10=18. These three stable forms of oxygen are called isotopes. ISOTOPES are atoms of an element that have the same number of protons, but different numbers of neutrons. Day 05­ Matter and the Atom
The Atomic Number you see on your periodic table is really the average atomic mass. It is a weighted average of the masses of all natural isotopes of an element by their abundance.
Different ways to write isotopes:
24
Mg
Mg­24 Magnesium­24 12
Calculating Average Atomic Mass
Find the average atomic mass of Magnesium.
1)
2)
Mg­24
23.985
78.70%
Mg­25
24.985
10.13%
Mg­26
25.983
11.17%
http://www.algebralab.org/practice/practice.aspx?file=algebra_averageatomicmass.xml
Day 05­ Matter and the Atom
3)
4)
Radioisotopes
Some isotopes are more unstable than others. In an unstable isotope, the nuclei are more likely to decay, releasing energy and subatomic particles. This process happens spontaneously and is called RADIOACTIVITY.
Radioactive isotopes are called RADIOISOTOPES for short. Uranium is an example of a radioisotope.
Questions
1. What is the relationship between the atomic number and the mass number of an element?
2. What is the difference between an isotope and a radioisotope?
Day 05­ Matter and the Atom
Standard Atomic Notation (Chemical Notation)
Chemists all over the world use this notation to show information about an elements protons and neutrons.
Example
Standard Atomic Notation for the two stable isotopes of Carbon is shown below.
For Carbon­12
Mass number = 12
= protons + neutrons
Atomic number = 6 = protons
Number of neutrons = 6
For Carbon­16
Mass number = 16 Atomic number = 6
Number of neutrons = 10
Day 05­ Matter and the Atom
Subatomic Particles Worksheet
Standard
Atomic
Notation
Atomic #
Mass #
Day 05­ Matter and the Atom
Mass #
Day 05­ Matter and the Atom
Mass #