1. Atomic Structure

2. Elements and Atoms Element- a pure substance made up of only one type of atom. Atom- smallest unit of an element that maintains the properties of that element.

3. Types of Elements 1.Metals- good conductor, lustrous, malleable, ductile. Left of zigzag line. 2.Nonmetals- poor conductor, most are gases at room temperature. Right of zigzag line. 3.Metalloids- characteristics of metals and nonmetals. On the zigzag line.

5. Inside the Atom Protons:1) positively charged particles 2) define the element 3) equal to the atomic number Neutrons: 1) neutrally charged particles 2) approximately the same size as protons (a bit more) Electrons: 1) negatively charged particles 2) A lot smaller than the protons or neutrons

7. On the Periodic Table you see… Atomic Number  Atomic Symbol  Avg. Atomic Mass  Element 

8. Understanding the Periodic Table Atomic Number: the unique number of an element defined by the number of protons Atomic Number: the unique number of an element defined by the number of protons Equals the number of electrons Equals the number of electrons Atomic Symbol: an abbreviation of an element Atomic Symbol: an abbreviation of an element Average Atomic Mass: the average of mass numbers of the isotopes of an element Average Atomic Mass: the average of mass numbers of the isotopes of an element

9. Isotopes atoms of the same element with different masses (mass numbers) same number of protons different number of neutrons Mass Number mass of protons + mass of neutrons This number can vary between atoms of an element.This number can vary between atoms of an element.

10. Three Isotopes of Hydrogen: Protium (99.9885%), Deuterium (0.0115%), Tritium Average atomic mass: 1.0079

11. Question All isotopes of hydrogen contain a. one neutronc. one proton b. two electronsd. two nuclei

12. Sample Mass Spectrometer Electron Field Accelerator Charged Particle Beam Magnet Heaviest Particles Lightest Particles Detector According to a mass spectrometer experiment, the following data is obtained using a Nitrogen sample: 99.64% atoms are N 14 isotopes 0.36% atoms are N 15 isotopes What is the weighted average?

14. Two ways to represent Isotopes of an atom: 1) Hyphen Notation: - element name – mass # Ex: hydrogen - 3 2) Nuclear symbol mass = upper left hand number # protons = lower left hand number Deuterium = 2 1 H Tritium = 3 1 H

15. Given the nucleus below: What is the mass number of this element? Which element is this?

16. The size of the nucleus:

17. Question Protons within a nucleus are attracted to each other by a. nuclear forces b. opposite charges c. their energy levels d. electron repulsion

18. Question The nucleus of an atom has all of the following characteristics EXCEPT that it The nucleus of an atom has all of the following characteristics EXCEPT that it a. is positively charged b. is very dense c. contains nearly all of the atom's mass d. contains nearly all of the atom's volume

19. The Charges: Proton: +1 mass = 1 amu Proton: +1 mass = 1 amu Neutron: 0 charge mass = 1amu Neutron: 0 charge mass = 1amu Electron: -1 mass =.00055 amu Electron: -1 mass =.00055 amu

20. Atomic Mass Unit (amu) 1 atom chosen arbitrarily for the standard 1 atom chosen arbitrarily for the standard carbon-12 has a mass of 12 amu carbon-12 has a mass of 12 amu 1amu = exactly 1/12 the mass of a carbon-12 atom 1amu = exactly 1/12 the mass of a carbon-12 atom The atomic mass of any atom is determined by comparing it to carbon The atomic mass of any atom is determined by comparing it to carbon

21. How many protons, electrons & neutrons are in Carbon 14? Protons: Always 6 in carbon Protons: Always 6 in carbon Electrons: Same as protons, or 6 Electrons: Same as protons, or 6 Neutrons = Mass# - protons Neutrons = Mass# - protons Neutrons: 14 - 6 = 8 neutrons Neutrons: 14 - 6 = 8 neutrons

22. Question An aluminum isotope consists of 13 protons, 13 electrons, and 14 neutrons. Its mass number is a. 13c. 27 b. 14d. 40

23. Question The atomic mass listed in the periodic The atomic mass listed in the periodic table is the: table is the: a. average atomic mass. b. relative atomic mass of the most abundant isotope. abundant isotope. c. relative atomic mass of the most stable radioactive isotope. stable radioactive isotope. d. mass number of the most abundant isotope. isotope.