1. Structure of Atoms Chapter 5

2. You will learn about: Structure of atoms Isotopes Electron arrangement in atoms The Periodic Table Ions You will learn about: Structure of atoms Isotopes Electron arrangement in atoms The Periodic Table Ions contents

3. Particle Relative Mass Relative Electric Charge proton1+1 neutron10 electron 1/2000  0 structure of atoms  three types of particles in an atom: proton, neutron and electron composition  consists of a nucleus surrounded by electrons in shells  nucleus in turn contains protons and neutrons  consists of a nucleus surrounded by electrons in shells  nucleus in turn contains protons and neutrons

4.  structure of an atom: composition structure of atoms  number of protons is the proton number (atomic number)  number of electrons = number of protons  atom is electrically neutral  total number of protons and neutrons is the nucleon number (mass number)  number of protons is the proton number (atomic number)  number of electrons = number of protons  atom is electrically neutral  total number of protons and neutrons is the nucleon number (mass number) + - structure of an atom electrons in shells around nucleus nucleus (protons + neutrons) -

5.  simplified structure of a typical atom: simplified structure structure of atoms structure of a carbon atom - + 6 6 6 nucleon number = 6 + 6 = 12 proton number = 6 - + electron proton neutron

6.  written in symbol form  symbol tells us that the atom Cl symbol form structure of atoms 35 17 proton number nucleon number symbol of the element o is of element chlorine o has proton number 17 (so it contains 17 protons) o has 17 electrons (number of protons = number of electrons) o has nucleon number 35 (so number of protons + number of neutrons = 35) o it must contain 35 – 17 = 18 neutrons

7. 11 number of protons 23 - 11 = 12 11 24 – 11 = 13number of neutrons 11number of electronsIsotopes Na Na24 11 23 11  are atoms of the same element with different numbers of neutrons  same proton number but different nucleon numbers (mass numbers)  are atoms of the same element with different numbers of neutrons  same proton number but different nucleon numbers (mass numbers) isotopes

8.  have same chemical properties and form compounds with the same formula because they have the same number and arrangement of electrons  have small differences in physical properties  can be radioactive or non-radioactive  have same chemical properties and form compounds with the same formula because they have the same number and arrangement of electrons  have small differences in physical properties  can be radioactive or non-radioactive isotopes

9. 82 and above 21 Maximum Number of Electrons Shell Number electron arrangement in atoms  electrons are arranged around the nucleus of the atom in shells  atomic nucleus (positive charge) attracts the electrons (negative charge) by an electrostatic force  each shell can hold a maximum number of electrons  electrons are arranged around the nucleus of the atom in shells  atomic nucleus (positive charge) attracts the electrons (negative charge) by an electrostatic force  each shell can hold a maximum number of electrons electrons  electrons always go into the shell nearest to the nucleus, if there is room; otherwise they go to the next available shell

10. electronic structure & outer electrons electron arrangement in atoms  is the arrangement of electrons in atoms  three ways of showing the electronic structure of a silicon atom:  is the arrangement of electrons in atoms  three ways of showing the electronic structure of a silicon atom: full electronic structure + - - - - - - - - - - - - + - - outer electronic structure valency electrons electronic structure 2.8.4 - - - - valence shell

11. electron arrangement in atoms  electronic structures of the first 20 elements: electronic structure & outer electrons

12. electron arrangement in atoms  electronic structures of the first 20 elements: electronic structure & outer electrons

13.  arrangement of elements in a table  periods show the elements arranged horizontally in order of proton number (atomic number)  across each period, the number of outer shell electrons increases from 1 to 8  groups show the elements with the same number of outer electrons arranged in vertical columns  arrangement of elements in a table  periods show the elements arranged horizontally in order of proton number (atomic number)  across each period, the number of outer shell electrons increases from 1 to 8  groups show the elements with the same number of outer electrons arranged in vertical columns the Periodic Table

14. group number simplified electronic structure IIIIIIIVVVIVII VIII full electronic structure the Periodic Table proton number name of element symbol

15. ions  are charged particles; can be either positively or negatively charged  atoms form ions by gaining or losing electrons to obtain the electronic structure of a noble gas  are charged particles; can be either positively or negatively charged  atoms form ions by gaining or losing electrons to obtain the electronic structure of a noble gas ions non-metallic atom takes in electron(s) Negative Ions metallictype of atoms atom loses electron(s) movement of electrons Positive Ions

16. ions  a negative ion is formed by gaining electrons to an atom  a positive ion is formed by losing electrons to an atom  a negative ion is formed by gaining electrons to an atom  a positive ion is formed by losing electrons to an atom ions 17 C l atom 18 17 C l - ion 8 8 O atom 10Number of electrons 8No of protons O 2- ion 11 Na atom 10 11 Na + ion 12 Mg atom 10Number of electrons 12No of protons Mg 2+ ion

17. Proton number Neutrons Protons Positive ions Negative ions Electrons Nucleon number Isotopes Periodic Table lose electrons to become gain electrons to become contain have shells members have same number of electrons in which give out radiation are negative charge are is the sum of contain contain are arranged in outer shell furthest from nucleus is electron arrangement is electronic structure group vertical column is have positive charge have different numbers of radioactive neutral contain contain nucleus elements in order of is the sum of Atoms