1. 4.2 > 4.2 Structure of the Nuclear Atom > 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 4 Atomic Structure 4.1 Defining the Atom 4.2 Structure of the Nuclear Atom 4.3 Distinguishing Among Atoms

2. 4.2 > 4.2 Structure of the Nuclear Atom > 2 Do Now: Fill in the table Hyphenated Notation ProtonsElectronsNeutronsMass Number Nuclear Symbol 3375 41 Ca 20 Cesium-13378 66 Zn 30

3. 4.2 > 4.2 Structure of the Nuclear Atom > 3 Do Now: Hyphenated Notation ProtonsElectronsNeutronsMass Number Nuclear Symbol Arsenic-7533 4275 75 As 33 Calcium-4120 2141 41 Ca 20 Cesium-13355 78133 133 Cs 55 Zinc-6630 3666 66 Zn 30

4. 4.1 Defining the Atom > 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Early Models of the Atom Democritus Greek philosopher (460 BC –370 BC) Reasoned atoms were indivisible & indestructible http://ed.ted.com/lessons/the-2-400-year-search-for-the- atom-theresa-doud

5. 4.1 Defining the Atom > 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Dalton English chemist & school teacher 1766 – 1864 Used experimental methods to transform Democritus’ ideas into scientific theory Studied ratios that elements combine in chemical reactions Early Models of the Atom

6. 4.1 Defining the Atom > 6 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Dalton’s Atomic Theory Atoms of element A Early Models of the Atom 1.All elements are composed of tiny indivisible particles called atoms.

7. 4.1 Defining the Atom > 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Dalton’s Atomic Theory Atoms of element A Atoms of element B Early Models of the Atom 2.Atoms of the same element are identical. The atoms of any one element are different from those of any other element.

8. 4.1 Defining the Atom > 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Dalton’s Atomic Theory Mixture of atoms of elements A and B Early Models of the Atom 3.Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds.

9. 4.1 Defining the Atom > 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Compound made by chemically combining atoms of elements A and B Dalton’s Atomic Theory Early Models of the Atom 4.Chemical reactions occur when atoms are separated from each other, joined, or rearranged in different combinations. Atoms of one element are never changed into atoms of another element as a result of a chemical reaction.

10. 4.2 > 4.2 Structure of the Nuclear Atom > 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Subatomic Particles In 1897, J. J. Thomson discovered the electron. https://www.youtube.com/watch?v=XU8nMKkzbT8 Electrons

11. 4.2 > 4.2 Structure of the Nuclear Atom > 11 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Plum Pudding Model Thomson’s atomic model Electrons stuck in a lump of positive charge, similar to raisins stuck in dough.

12. 4.2 > 4.2 Structure of the Nuclear Atom > 12 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The Atomic Nucleus Rutherford’s Gold-Foil Experiment Narrow beam of alpha particles was directed at a thin sheet of gold.

13. 4.2 > 4.2 Structure of the Nuclear Atom > 13 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The Atomic Nucleus Rutherford’s Gold-Foil Experiment Some alpha particles bounced off the gold foil https://www.youtube.com/watch?v=5pZj0u_XMbc

14. 4.2 > 4.2 Structure of the Nuclear Atom > 14 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The Atomic Nucleus The Rutherford Atomic Model Protons and neutrons are in the nucleus Electrons distributed around nucleus and occupy almost all of the volume of the atom Did NOT explain chemical properties of elements

15. 5.1 Revising the Atomic Model > 15 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Each possible electron orbit has a fixed energy known as an energy level. Energy Levels in Atoms The Bohr Model Quantum of Energy Amount of energy required to move an electron from one energy level to another.

16. 5.1 Revising the Atomic Model > 16 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Energy Levels in Atoms Electrons cannot exist between energy levels. Energy levels are unequally spaced Higher energy levels are closer together The Bohr Model

17. 5.1 Revising the Atomic Model > 17 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Energy Levels in Atoms When an electron occupies the lowest possible energy level it is said to be in its ground state. Electron can absorb energy (become excited) from external sources:  Sun  Fire (heat)  Electricity The Bohr Model

18. 5.1 Revising the Atomic Model > 18 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Energy Levels in Atoms When electrons absorb energy, they can jump to higher levels. This is called the excited state. When electrons return to the ground state, it releases energy in the form of light. Emission Line Spectra The Bohr Model

19. 5.1 Revising the Atomic Model > 19 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Energy Levels in Atoms Each orbital can hold a specific number of electrons. Maximum # electrons = 2n 2 The Bohr Model Orbital (n) Max # Electrons 12 28 318 432

20. 5.1 Revising the Atomic Model > 20 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Energy Levels in Atoms 1.Draw a circle to represent the nucleus. 2.Determine the number of protons and neutrons and place them in the nucleus. 3.Draw circles around the nucleus to represent the electron shells. 4.Place the electrons in the shells. Neon The Bohr Model p + =10 n 0 =10

21. 5.1 Revising the Atomic Model > 21 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Quantum Mechanical Model Electron does not have an exact orbit. Atomic Orbital – region of space where there is a high probability of finding an electron. The Quantum Mechanical Model Electron cloud

22. 5.1 Revising the Atomic Model > 22 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Atomic Orbitals Energy Level (n) Indicates shell occupied by electron n =1,2,3,4,5,6,7 Corresponds to period (row) on periodic table Also called Principal Quantum Number

23. 5.1 Revising the Atomic Model > 23 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Atomic Orbitals Sublevels Each energy level contains sublevels Sublevels contain orbitals of different shapes and energies.

24. 5.1 Revising the Atomic Model > 24 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Atomic Orbitals Sublevels # of sublevels within an energy level is equal to the principle quantum number For example, n = 1 has 1 sublevel n = 2 has 2 sublevels

25. 5.1 Revising the Atomic Model > 25 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Atomic Orbitals Summary of Principal Energy Levels and Sublevels Principal energy level (n) Number of sublevels Type of sublevel (n 2 ) Maximum number of electrons (2n 2 ) n = 111s (1 orbital)2 n = 222s (1 orbital), 2p (3 orbitals)8 n = 33 3s (1 orbital), 3p (3 orbitals), 3d (5 orbitals) 18 n = 44 4s (1 orbital), 4p (3 orbitals), 4d (5 orbitals), 4f (7 orbitals) 32

26. 5.1 Revising the Atomic Model > 26 Quantum Numbers The building = atom Apartment Floors = Energy Levels (shells) Specific Apartments = Orbitals (subshells) Residents = Electrons

27. 5.1 Revising the Atomic Model > 27 Quantum Numbers