DAILY QUESTION September 30, What are the three subatomic particles found in an atom called and what are their charges?

Agenda9/30/08 Daily Question Chapter 4, Section 1 Notes Assignments: 1. Ch 4 Section 1 Wksht due 10/1

Atoms (page ) The smallest part of an element that still has the element’s properties Combine to make molecules –Examples: H 2 O Whether 1 molecule or billions, they are always the same: 2 hydrogen to 1 oxygen

What’s in an Atom? (page 106) Subatomic particles ProtonNeutronElectron Positive Charge Negative Charge No Charge Found in Nucleus Found in Nucleus Found surrounding Nucleus Very little mass Same mass as a proton Same mass as a neutron Same size as a proton Same size as a neutron Very small size

“Happy Atoms” An unreacted atom is “neutral” –The number of protons = the number of electrons

Models of Atoms (page 107) Bohr’s Model Electrons move in set paths around nucleus Energy levels are determined by path Must gain or lose energy to move levels

Models of Atoms (page 107) Modern Model Electrons behave more like waves

Locating Electrons (page 108) It is impossible to determine both the exact location of an electron in an atom and the electron’s speed and direction Best they can do is shade the area where there is a better chance that electrons will be… the shaded region is called the electron cloud

Energy Level of Electrons (page 108) Electrons can be found in different energy levels Each energy level can hold a certain number of electrons –Energy level 1 – 2 electrons –Energy level 2 – 8 electrons –Energy level 3 – 18 electrons –Energy level 4 – 32 electrons

Orbitals within Energy Levels (page 109) Orbitals are regions in an atom where electrons are likely to be found Electrons occupy orbitals with the lowest energy Four Kinds of Orbitals: s, p, d, f

s Orbital Shaped like a sphere Can only be oriented one way Lowest energy Can hold two electrons

p Orbital Dumbbell shaped Can be oriented in three ways (X, Y, Z axes) Has more energy than an s orbital Each p orbital can hold 2 electrons, –There are three, for a total of 6 electrons

d and f orbitals There are 5 possible d orbitals There are 7 possible f orbitals –f orbitals have the greatest energy Each orbital can only hold a maximum of 2 electrons

Valence Electrons (page 110) An electron in the outermost energy level Determine an atom’s chemical properties Determines the ability to bond