CHEMICAL BONDS AND STABILITY

1. CHEMICAL BONDS AND STABILITY 8th Grade Science – Kawameeh Middle School

2. How do atoms bond? TRANSFERRING • Atoms bond by or electrons. SHARING • An atom’s depends on how likely it will . STABILITY REACT

3. Why do atoms bond? STABLE ATOMS • want to be therefore they want their energy filled. OUTER-MOST LEVEL 8 VALENCE • electrons (with the exception of having • electrons) make a HELIUM 2 VALENCE STABLE ATOM.

4. Atoms react or BOND in two ways: LOSES 1. An atom electrons to become POSITIVE GAINS 2. An atom electrons to become NEGATIVE

5. CHEMICAL BOND • The of that FORCE ATTRACTION HOLDS TWO ATOMS TOGETHER

6. Reactive Metals and Nonmetals • Elements that have react easily with whose atoms 1 • Which group has 7 valence electrons? • Which group has 1 valence electron? 7 VALENCE ELECTRONS ELEMENTS GIVE UP OR SHARE ELECTRON 17 – very reactive 1 – very reactive

7. Reactive Metals and Nonmetals 1 2 • Usually elements have , or will their electrons. • Elements with , or will electrons. 3 VALENCE ELECTRONS LOSE 5 6 7 VALENCE ELECTRONS GAIN

8. Nonmetals • Have or more • Bond with by electrons. • and bond by electrons. 4 VALENCE ELECTRONS METALS GAINING NONMETALS NONMETALS SHARING

9. THERE ARE TWO TYPES OF BONDS • IONIC BONDS • COVALENT BONDS

10. IONIC BONDS • Atoms transfer VALENCE ELECTRONS to reach stability. • **Atoms with 5, 6 or 7 valence electrons • ** Atoms with 1, 2 or 3 valence electrons GAIN ELECTRONS TO BE STABLE LOSE ELECTRONS TO BE STABLE

13. Lithium, Fluorine, Neon • Lithium – Gives 1 Valence Electron • Fluorine – Takes 1 valence electron to become stable. • Neon – does not take or give any electrons. Neon is in group 18 and is already stable.

14. Ionic Bonds LOSES GAINS • When an atom or valence the becomes or electrically charged. • Ion - ELECTRONS ATOM NEGATIVELY POSITIVELY An atom or group of atoms that has an electric charge (+ or - )

15. LOSING VALENCE ELECTRONS GIVES YOU +++++POSITIVE IONS

16. LOSING VALENCE ELECTRONS GIVES YOU…. +++ POSITIVE IONS+++ • When an atom an it becomes charged. • WHY DOES THIS HAPPEN? LOSES ELECTRON POSITIVELY

17. GAINING VALENCE ELECTRONS GIVES YOU…---NEGATIVE IONS--

18. GAINING VALENCE ELECTRONS GIVES YOU… • When an atom an it becomes charged. • WHY DOES THIS HAPPEN? ---NEGATIVE IONS--- GAINS ELECTRON NEGATIVELY

21. REVIEW: HOW IONIC BONDING WORKS • Atoms become charged • Transferring valence electrons cause ions to be formed • Opposite ions attract each other

22. COVALENT BOND • A chemical bond formed when two atoms share electrons. (Uncharged) • ***Covalent bonds usually form between and . • The of the of each holds the together when NONMETALS NONMETALS FORCE ATTRACTION ATOMS NUCLEUS SHARING ELECTRONS

23. COVALENT BOND • ** A molecule is • **Remember** Atoms bond to reach (Helium 2 v.e.) which makes the • Molecular Compound: A that is of A NEUTRAL GROUP OF ATOMS JOINED BY COVALENT BONDS. COVALENTLY 8 VALENCE ELECTRONS COMPOUND STABLE COMPOUND MADE MOLECULES COVALENTLY BONDED

25. Practice 1: Nitrogen + 3 Hydrogen

26. Practice 2: 2 Hydrogen + Oxygen

27. Practice 3: Chlorine + Chlorine

28. Practice 4: Carbon + 2 Oxygen

29. Oxygen + Oxygen

30. Carbon + 2 Oxygen

31. Carbon + 4 Hydrogen

32. Hydrogen + Hydrogen