Presentation on theme: "Properties of Atoms and the Periodic Table"— Presentation transcript:
1 Properties of Atoms and the Periodic Table Chapter 17Properties of Atoms and the Periodic Table
2 Section 1 – Structure of the Atom Look at elements and their symbols
3 What’s in an atom?Atom: smallest piece of matter that still is the elementNucleus: positively charged center of atom containingProtons: particle with 1+ chargeNeutrons: particle with NO chargeElectrons: surround nucleus in cloud and have 1- charge
4 Even smaller… Quarks: make up protons and neutrons NOT electrons Found using a particle acceleratorSpeed up particles and smash them into each otherFound 6 quarks
5 Models Represent things that are hard to visualize Model of the atom has changed many timesPg. 510 in book
6 Today’s model of atomElectron cloud model: nucleus in middle and cloud around nucleus where electrons are most likely found
7 Section 2 – Masses of Atoms Nucleus has most of massProton: x gNeutron: x gElectron: x gMass of proton and neutron are about 2,000 times bigger than electron!!
8 Atomic Mass Need better numbers for masses Atomic Mass Unit (amu) Proton: 1 amuNeutron: 1 amuElectron ~ negligible
9 Protons Identify Element Each element has different # of protonsThe number of protons tells you what type of element you haveAtomic Number: the number of protons
10 Mass Number Mass Number: SUM of protons and neutrons # of neutrons = mass # - atomic #Carbon – 12 and Carbon – 14Mass Number
11 Mass Number How many neutrons are in the Carbon-14 atom? Sodium has a mass number of 23. How many protons and neutrons does it have?Copper – 63: how many protons and neutrons?
12 IsotopesDef: atoms of the same element that have different # of neutronsIsotopes: Boron – 10 and Boron – 11Average Atomic Mass: weighted-average mass of mixture of isotopes
13 Calculating Average Atomic Mass Four out of five boron atoms are boron-11 and one out of five are boron-10. What is the AAM?
15 Organizing the Elements Periodic – repeated in a patternLate 1800s – Dimitri Mendeleev – Russian – organized elements by increasing massesDiscovered a pattern with chemical properties, they repeated Periodic
17 Current Periodic Table 1913 – Henry Moseley – English – organized elements by increasing atomic number
18 The Atom and the Periodic Table Vertical columns = Groups / FamiliesUse A group numberingFamilies have similar properties
19 Location of Electrons In neutral atom, # of protons = # of electrons Energy levelsclose to nucleus = low energyfarther away = higher energy
20 Energy Levels and Electrons Same group = same # of e- in outer energy levelEnergy levels are 1 – 7Filled outer energy level = 8 e-Levels 3 and higher have inner sub-levels
21 Energy Levels and Electrons Horizontal rows = PeriodsIncrease by 1 p+ and 1 e- as you move rightEach row ends with atom with filled outer energy level
22 Electron Dot Diagrams Group #s = # valence e-s (outer e-s) Def: uses the element symbol and dots to represent outermost electronsAtoms bond to get a filled outer energy levelWhich groups would likely react?
23 Regions of the Periodic Table Metals, Non-metals, and Metalloids
24 MetalsConductors of heat and electricityLuster/shineMostly solid
25 Nonmetals Poor conductors of heat and electricity Many are gases Solids are brittle
26 MetalloidsSemiconductors of heat and electricity