Why can’t you just draw an atom? Why do you need to designate which element you are going to draw? Does this have to do with the number of protons, neutrons and electrons an atom has? Is this what makes each element different?
1. Integrated Science Unit 6, Chapter 18
2. Unit Six: Properties of Matter Chapter 18 Atoms and Elements18.1 Atomic Structure18.2 Comparing Atoms18.3 The Periodic Table of Elements
3. Chapter 18 Learning Goals1. Build models of atoms.2. Understand how atoms of each element differ.3. Describe the forces that hold an atom together.4. Understand how elements are organized in the periodic table.5. Use the periodic table to identify the atomic number and mass numbers of each element.
4. Chapter 18 Vocabulary Terms atomic mass electrons  neutrons atomic mass units  nucleus atomic number  periodic table of elements atomic theory  protons energy levels  strong nuclear force group of elements  subatomic particles isotopes  valence electrons mass number
5. Title: 18.1 Atomic Structure *Allmatter is formed from atoms. *Ifbroken apart, almost all atoms contain three smaller particles called protons, neutrons, and electrons. Protons and neutrons cluster together in the atom’s center, called the nucleus.
6. * Protons and Neutrons: *Protons are positively charged particles found in the atoms center, called the nucleus *Neutronsare particles found in the center of the atom that have no charge
7. * Nucleus: *Thenucleus is the center of the atom, where the protons and neutrons cluster together
8. * Electrons: *Electronsare negatively charged particles found circulating around the atom. *Theyare much smaller than protons and neutrons. *They move around the atom in a fixed orbit
9. 18.1 Atomic Structure *Atoms and molecules are called the building blocks of matter. Atoms are very small. Subatomic particles have charge and mass: — proton (p+) = 1 amu — neutron (n0) = 1 amu — electron (e-) = 1/2000 amu
10. John Dalton’s Contributions:
11. 18.1 Changing model of the atom John Daltons Atomic Theory 18081. Each element is composed of extremely small particles called atoms.2. All atoms of a given element are identical.3. Atoms of different elements have different properties, including mass and chemical reactivity.4. Atoms are not changed by chemical reactions, but merely rearranged into different compounds.5. Compounds are formed when atoms of more than one element combine.6. A compound is defined by the number, type (element), and proportion of the constituent atoms.
12. 18.1 Changing model of the atom Dalton pictured the atom as a small hard sphere.
13. 18.1 Changing model of the atom TheThompson model suggested negative electrons were embedded in a positive sphere.
14. 18.1 Changing model of the atom Bohrsmodel showed electrons moving around the nucleus in fixed orbits.
15. Neils Bohr’s Atomic Theory
16. 18.1 Changing model of the atom Schrödingersmathematical model demonstrated that the electron position could be predicted, but not pinpointed exactly. **Schrödingers model is called the Electron Cloud Model. The cloud represents the probable locations of an electron in its orbit around the nucleus.
17. Your Turn… Draw and label the parts of a carbon atom Include: — Nucleus — Protons — Neutrons — Electrons
18. 18.1 Atomic StructureKey Question:How was the size of an atoms nucleus discovered ? *Read text section 18.1 BEFORE Investigation 18.1