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Turn in homework (78, 1-6) and test corrections in box Objectives : Name and describe the mass and charge of the subatomic particles. Find the number of protons, neutrons, and electrons in typical atoms. Catalyst 11/1/10.
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Turn in homework (78, 1-6) and test corrections in box Objectives: Name and describe the mass and charge of the subatomic particles. Find the number of protons, neutrons, and electrons in typical atoms. Catalyst 11/1/10 1. Given the information in the chart, if a student were to apply heat to equal volumes of all four liquids along with a volume of water, which liquids would boil before the water? A. Q and S B. R and T C. Q and R D. S and T2. If a student is performing an experiment that requires a liquid that has a density less than water, has a higher boiling point than water, and has a distinctive odor, which of the liquids on the chart would be best to use? A. Q B. R C. S D. T
Agenda • Subatomic Particle Notes (15-30) • Ion and Isotope Notes (30) • Homework: • Write the Name, Symbol, atomic mass, atomic number, # protons, # neutrons and # electrons of the first 20 elements
Dalton’s Atomic theory • Support for his theory came when he began looking at the masses of elements that combined with each other. • He found that elements combine in simple ratios by mass.
Dalton’s atomic theory • Dalton’s atomic theory • all matter is composed of tiny, indivisible particles called atoms. • All atoms of the same element are identical in properties • Atoms of different elements differ in properties. • Atoms can neither be created nor destroyed. • Atoms of two or more different elements can combine in small whole number ratios to form compounds.
Dalton’s atomic theory • 2 problems with his theory: • Atoms of the same element can have different masses • atoms have subatomic particles (electrons, protons and neutrons) So Dalton’s theory is not completely correct.
Two major parts of an atom Nucleus (not to scale) Electron Cloud
Three Major Sub-Atomic Particles • Protons • Neutrons • Electrons
PROTON (p+) a single, relatively large particle with apositive charge that isfound in the nucleus
p+ THE PROTON • Fat (heavy) • Positive (charge) • Doesn’t move (lazy)
NEUTRON (N°) a single, relatively large particle with aneutral charge that isfound in the nucleus
N° THE NEUTRON • Fat (heavy) • Neutral (charge) • Doesn’t move (lazy)
ELECTRON (e-) a single, very small particle with anegative charge that isfound in a “cloud” around the nucleus
e- THE ELECTRON • Skinny (very light) • Negative (charge) • Moves a lot (runs around)
Where are they located? Nucleus: Protons and Neutrons Electron Cloud: Only Electrons
Atoms to Elements • What makes elements different from one another? • The number of protons! Also called the atomic number.
Chemical Symbols • Elements have a single capitalized letter for their symbol or have two letters-the first is capitalized and the second is lower case.
the number of protons in an atom ATOMIC NUMBER (Z)
ATOMIC MASS # (A) The total mass of all of the subatomic particles in an atom (but really # of protons and neutrons)
ELEMENTS Elements are electrically neutral. (They have the same # of p+ and # of e-)
Example: Sodium Atomic Mass # = p+ & N° 22.99 Round this number to the nearest whole number!!! Na 11 Atomic # = # of protons
Another Notation Atomic Mass # = p+ & N° Atomic # = # of protons
To calculate the number of neutrons, subtract the atomic number (smaller) from the atomic mass number (larger)A – Z = # of neutrons
Ex: How many neutrons does Sodium have? Mass # - Atomic # = #N° (You may need to round the atomic #) 22.99 23 - 11 = 12 N° Na 11
Atomic Mass Symbol Atomic Number
Hydrogen Protons: 1 Neutrons: 0 Electrons: 1 H 1 1
Sodium Protons: 11 Neutrons: 12 Electrons: 11 Na 23 11
Rhenium Protons: 75 Neutrons: 111 Electrons: 75 Re 186 75
ION Atoms of the same element that differ in charge.(They have the same # of p+, but different # of e-)
Ex: How many electrons does Sodium have? The atomic number equals the number of protons and the number of electrons. 22.99 11 electrons Na 11
Negative Ions(anions) Positive Ions(cations) • Na+ (lost 1 e-) • Ca2+ (lost 2 e-) • Al3+ (lost 3 e-) • Pb4+ (lost 4 e-) • H+ (lost 1 e-) • Cl- (gain 1 e-) • O2- (gain 2 e-) • P3- (gain 3 e-) • S2- (gain 2 e-) • OH- (gain 1 e-)
If an atom GAINS electrons, its overall charge becomes more negative.If it LOSES electrons, its charge becomes more positive
Learning Check – Counting State the number of protons, neutrons, and electrons in each of these ions. 39 K+16O -241Ca +2 19 8 20 #p+ ______ ______ _______ #no ______ ______ _______ #e- ______ ______ _______
ISOTOPE Atoms of the same element that differ in mass.(They have the same # of p+, but different # of N°)
Isotopes are CHEMICALLY the SAME as atoms, but DIFFER PHYSICALLY because they have different masses.
Learning Check – Counting Naturally occurring carbon consists of three isotopes, 12C, 13C, and 14C. State the number of protons, neutrons, and electrons in each of these carbon atoms. 12C 13C 14C 6 6 6 #p+ _______ _______ _______ #no _______ _______ _______ #e- _______ _______ _______
Answers 12C 13C 14C 6 6 6 #p+666 #no678 #e- 6 66
One Last Learning Check Write the nuclear symbol form for the following atoms or ions: A. 8 p+, 8 n, 8 e- ___________ B. 17p+, 20n, 17e- ___________ C. 47p+, 60 n, 46 e- ___________
So, why do the elements on the PT have masses with decimals???
The periodic table has the average atomic mass of all of the isotopes of a substance
11B 10B AVERAGE ATOMIC MASS • Because of the existence of isotopes, the mass of a collection of atoms has an average value. • Boron is 20% 10B and 80% 11B. That is, 11B is 80 percent abundant on earth. • For boron atomic weight = 0.20 (10 amu) + 0.80 (11 amu) = 10.8 amu
Average atomic mass is calculated by: • Mass each isotope and multiply by amount • Add calculations for each isotope • Divide sum by the total amount