phy scie day 1 ionic bond.ppt
- 2. Electrons are placed in shells according to rules: 1) The 1st shell can hold up to two electrons, and each shell thereafter can hold up to 8 electrons.
- 3. Octet Rule = atoms tend to gain, lose or share electrons so as to have 8 electrons C would like to N would like to O would like to Gain 4 electrons Gain 3 electrons Gain 2 electrons
- 4. Why are electrons important? 1) Elements have different electron configurations different electron configurations mean different levels of bonding
- 6. Chemical bonds: an attempt to fill electron shells 1. Ionic bonds – 2. Covalent bonds – 3. Metallic bonds
- 7. Learning Check A. X would be the electron dot formula for 1) K 2) H 3) Al B. X would be the electron dot formula 1) B 2) N 3) P
- 8. IONIC BOND bond formed between two ions by the transfer of electrons
- 9. Ionic Bond • Between atoms of metals and nonmetals with very different electronegativity • Bond formed by transfer of electrons • Produce charged ions all states. Conductors and have high melting point. • Examples; NaCl, CaCl2, K2O
- 10. Formation of Ions from Metals Ionic compounds result when metals react with nonmetals Metals lose electrons to match the number of valence electrons of their nearest noble gas Positive ions form when the number of electrons are less than the number of protons Group 1 metals ion 1+ Group 2 metals ion 2+ • Group 13 metals ion 3+
- 11. Formation of Sodium Ion Sodium atom Sodium ion Na – e Na +
- 12. Formation of Magnesium Ion Magnesium atom Magnesium ion Mg – 2e Mg2+
- 13. Some Typical Ions with Positive Charges (Cations) Group 1 Group 2 Group 13 H+ Mg2+ Al3+ Li+ Ca2+ Na+ Sr2+ K+ Ba2+
- 14. 1). Ionic bond – electron from Na is transferred to Cl, this causes a charge imbalance in each atom. The Na becomes (Na+) and the Cl becomes (Cl-), charged particles or ions.
- 16. COVALENT BOND bond formed by the sharing of electrons
- 17. Covalent Bond • Between nonmetallic elements of similar electronegativity. • Formed by sharing electron pairs • Stable non-ionizing particles, they are not conductors at any state • Examples; O2, CO2, C2H6, H2O, SiC
- 18. 2. Covalent bonds- Two atoms share one or more pairs of outer-shell electrons. Oxygen Atom Oxygen Atom Oxygen Molecule (O2)
- 20. • To determine the polarity in a bond between two atoms, you must use the value for electronegativity. • TYPES OF BOND BASED ON ΔEN OF BOUNDED ATOMS ΔEN BOND TYPE 0 Nonpolar covalent Greater than 0 up to 1.8 Polar covalent Greater than 1.8 Ionic
- 21. • A polar covalent bond is one in which a shared pair of electrons is held more closely to one atom. • A non-polar covalent bond is one in which the electrons are shared equally.
- 22. • A dipole is a molecule or part of a molecule that contains both positively and negatively charged regions.
- 23. Example • C and CL »C = 2.5 »Cl = 3.0 • ΔEN= 3.0 – 2.5 = 0.5 (polar covalent) • Mg and O »Mg = 1.2 »O = 3.5 • ΔEN= 3.5 – 1.2 = 2.3 (ionic)
- 24. Molecular Polarity • The polarity of a molecule (compound) depends on two things. • The polarity of the bonds. • The shape of the molecule.
- 25. METALLIC BOND bond found in metals; holds metal atoms together very strongly
- 26. Metallic Bond • Formed between atoms of metallic elements • Electron cloud around atoms • Good conductors at all states, lustrous, very high melting points • Examples; Na, Fe, Al, Au, Co
- 27. Metallic Bonds: Mellow dogs with plenty of bones to go around.
- 28. Ionic Bond, A Sea of Electrons
- 29. Metals Form Alloys Metals do not combine with metals. They form Alloys which is a solution of a metal in a metal. Examples are steel, brass, bronze and pewter.
- 30. Practice • Compute the mass of the following compounds round to nearest tenth & state type of bond: • NaCl; • 23 + 35 = 58; Ionic Bond • C2H6; • 24 + 6 = 30; Covalent Bond • Na(CO3)2; • 23 + 2(12 + 3x16) = 123; Ionic & Covalent