Presentation on theme: "Instructional Objective: 1. Learn the atomic models 2"— Presentation transcript:
1 Instructional Objective: 1. Learn the atomic models 2 Instructional Objective: 1.Learn the atomic models 2.Learn the atomic structure and elements.
2 History of the Atomic Model The Greek ModelDalton’s ModelThomson’s ModelRutherfords ModelBohr’s ModelThe Wave-Particle Model
3 The Greek ModelProposed around 400 B.C. By the Greek Philosopher DemocratsCalled them “Atomos”, in Greek means can’t be divided or destroyed.
4 John Dalton’s ModelProposed the Atomic Theory in 1803All atoms are made up of solid indivisible particles.* Elements differ in their atom’s size
5 J. J. Thomson’s Model Proposed in 1897 “raisin bread”model Believed that protons and electrons were mixed togetherKnown as the “plum pudding” or“raisin bread”model
6 Ernest Rutherford’s Model Proposed in 1907 after discovering atom’s nucleusElectrons move around a central nucleuscontaining protons..
7 Niels Bohr’s ModelElectrons move in energy levels around a central nucleusElectrons can only be in these energy levels.
8 Particle-Wave Model James Chadwick discovers neutron in 1935. Electrons are most likelyfound in energy levels
9 What is an Atom? *The smallest unit of a matter is known as an atom What is an element?An element is made up of only one kind of atom.What is a molecules ?Is the smallest unit of a compoundWhat is a substance?any element or compound
10 Structure of an atomAn atom is made up of a nucleus that contain protons and neutrons.And an outer orbit that contain electrons.-Protons are always positive in charge-Electrons are negative in charge-Neutrons are neutral or without any charge
11 Characteristics of an Atom Atom itself has no charge because protons are always equal to electrons.Ex: Sodium –Protons are 11--Electrons are also 11( Positive and negative will cancel each other)
12 Properties of subatomic particles Protons, electrons and neutrons are the subatomic particlesProtons are always positive in chargeElectrons are negative in chargeNeutrons are neutral or with out any charge
13 Difference between atomic mass and Atomic number Atomic mass: is the total number of protons and neutrons in the nucleus.Atomic number: Is the total number of protons
14 Element Block from periodic table atomic number Cl SymbolChlorine –Nameatomic massormass number17ClChlorine35.45
15 Other Symbols to remember p+ →Proton(always positive charge)e- → electron (always negative in charge)N0 → Neutrons(zero charge)<→Less than> →greater than+ → and or plus→ → yield(s) → solid(l) → Liquid(g) → gas
16 ISOTOPES.Atoms of the same element that have different number of Neutrons.Ex: The most common isotope of hydrogen.-Hydrogen has no neutrons at all(1proton)-Deuterium, with one neutron (1proton+1neutron)- Tritium, with two neutrons.(1proton+2 neutrons)
17 Isotopes can be written as the part of a chemical symbol Ex: N or Nitrogen – 15 ( 15 is the mass number and 7 is the atomic number)Ex: 3517Cl or Chlorine -35( 35 is the mass number and 17 is the atomic number)Close to the atomic mass, abundant is the element in that Isotope.
18 How are electrons arranged in an atom Electron CloudThe area in an atom where electrons are foundEnergy levelsIs the place in the electron cloudAre in different distance from nucleusThe closest to nucleus –less and weakFar away from nucleus –more and more powerful
19 The energy levels 1st- contain maximum 2 2nd- contain maximum 8 3rd- contain maximum 184th - contain maximum 32
20 Electron Configurations * Is the arrangement of electrons in the orbitals of an atom.
21 Electron configuration S orbit- 2 electronsP orbit-6 electronsD orbit-10 electronsF orbit – 14 electrons