7.4 Using the Bohr Theory

Transcription

1 7.4 Using the Bohr Theory

2 BOHR DIAGRAMS Practice (worksheet) First shell: 2 electrons Second shell: 8 electrons Third shell: 8 electrons Fourth shell: 8 electrons Draw Bohr Diagrams for: hydrogen sodium phosphorus neon calcium

3 BOHR DIAGRAMS for Ions NEUTRAL ATOM When a neutral atom gains or loses electrons How many electron(s)? How many protons? OVERAL charge? ION How many electron(s)? How many protons? OVERAL charge?

4 Patterns of Electron Arrangement in Groups If there are 8 electrons in the last shell = STABLE OCTET 1 exception = HELIUM (2 electrons) Which group has a STABLE OCTET in its outer most shell?

5 ATOMS WANT TO HAVE A STABLE OCTET!!!!!! ALL THE TIME!! If there are 8 electrons in a shell = STABLE OCTET All ATOMS want to be like NOBLE GASES!

6 Valence Shell = OUTERMOST SHELL

7 VALENCE ELECTRONS Electrons in the VALENCE SHELL are called VALENCE ELECTRONS

8 How many VALENCE ELECTRONS in GROUP 1?

9 How many VALENCE ELECTRONS in GROUP 2?

10 How many VALENCE ELECTRONS in GROUP 16?

11 How many VALENCE ELECTRONS in GROUP 18?

12 What Do You Notice about the Number of Valence Electrons for Elements in the Same Group? Most elements in the same group have the same number of valence electrons

13 What Do You Notice About the Placement and the Number of Valence Electrons for Elements in the Same Period? Elements in the same period have valence electrons in the same shell AND the number of valence electrons is increasing going left to right within the group by one

14 What Do You Notice About the period number and the number of occupied shells for Elements in the Same Period? The period number indicates the number of shells that have electrons.

15 ATOMS WANT TO HAVE A STABLE OCTET!!!!!! ALL THE TIME!! If there are 8 electrons in a shell = STABLE OCTET All ATOMS want to be like NOBLE GASES!

16 Unreactive because their atoms have filled valence shells = they are stable = NOBLE GAS STABILITY UNREACTIVE = they do not lose or gain electrons NOBLE GASES!

17 Each atom wants to have as many of valence electrons as the nearest noble gas. Metals want to LOSE ELECTRONS

18 How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST NOBLE GAS An atom of any metal can lose electrons and form positive ions

19 Each atom element to have as many of valence electrons as the nearest noble gas. Non - Metals want to GAIN ELECTRONS

20 How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST NOBLE GAS An atom of any non-metal except a noble gas can gain electrons and form negative ions

21 Each atom element to have as many of valence electrons as the nearest noble gas. 10 electrons How many electrons does sodium, Na, want to have?

22 Each atom element to have as many of valence electrons as the nearest noble gas. 10 electrons How many electrons does oxygen, O, want to have?

23 How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST NOBLE GAS Ions have the same electron arrangement as the nearest noble gas

24 What Element is this? 18 p 22 n argon

25 Bohr Diagrams Worksheet 1. How many protons does this element have? 2. How many electrons does this element have? 3. How many valence shells does this element have? 4. How many valence electrons does this element have? 5. How many occupied shells does this element have? 6. What is the identity of this element?

26 BOHR DIAGRAMS Practice (worksheet) First shell: 2 electrons Second shell: 8 electrons Third shell: 8 electrons Fourth shell: 8 electrons Draw Bohr Diagrams for: hydrogen Sodium ion Phosphorus ion Neon ion calcium ion

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33 MOLECULES and IONIC COMPOUNDS Atoms combine with different atoms to form compounds (thanks to electrons) Forces that hold atoms together are called CHEMICAL BONDS SHARING ELECTRONS Covalent Bonds DONATING ELECTRONS Ionic Bonds

34 MOLECULES and IONIC COMPOUNDS Atoms combine with different atoms to form compounds (thanks to electrons) Forces that hold atoms together are called CHEMICAL BONDS MOLECULES Covalent Bonds IONIC COMPOUNDS Ionic Bonds

35 MOLECULES and IONIC COMPOUNDS Forces that hold atoms together are called CHEMICAL BONDS These bonds arise when VALENCE ELECTRONS interact Each atom attempts to have as many of valence electrons as the nearest noble gas.

36 IONS Atom or a group of atoms with net negative or positive charge POSITIVELY CHARGED ION = CATION NEGATIVELY CHARGED ION = ANION

37 IONIC COMPOUNDS Formed by an attraction of positively charged ion and negatively charged ion Chemical formula

38 IONIC COMPOUNDS Formed when electrons are transferred from a metal to a non - metal Chemical formula

39 IONS Cations and Anions are attracted to each other IONIC BONDING

40 Draw the Bohr model diagram for NaCl

41 Draw the Bohr model diagram for NaCl

42 Draw the Bohr model diagram for NaCl

43 Draw the Bohr model diagram for KF

44 Draw the Bohr model diagram for CaF

45 MOLECULES and IONIC COMPOUNDS Atoms combine with different atoms to form compounds (thanks to electrons) Forces that hold atoms together are called CHEMICAL BONDS SHARING ELECTRONS Covalent Bonds DONATING ELECTRONS Ionic Bonds

46 Covalent Bonds Valence Electrons are shared between atoms

47 Covalent Bonds Unpaired electronsfrom each atom will pair together, forming a covalent bond. These two electrons are sometimes called a bonding pair. BONDING pair of electrons + hydrogen fluorine electrons are shared Hydrogen fluoride

48 Covalent Bonds An unpaired electron from each atom will pair together, forming a covalent bond. These two electrons are sometimes called a bonding pair. H 2 F 2 CF 4