Atomic Masses Test Friday!. Atomic Mass is an average (decimal) An average of known isotopes for an element The atomic mass of an element is closest to.

Slides:

Advertisements

Similar presentations

4.3: HOW ATOMS DIFFER ATOMIC NUMBER

Advertisements

Average Atomic Mass. How much does an atom weigh?  Protons & Neutrons:  1.67 X gram  Electrons:  9.10 X gram  To avoid working with.

Atomic Structure Nucleus – contains protons and neutrons

Chapter 11B Notes Determining Isotope Masses. Intro What is the mass of an atom with 6 protons and 6 neutrons? 12 What is the mass of an atom with 6 protons.

OF PROTONS, NEUTRONS AND ELECTRONS IN AN ATOM

The Atom & the Periodic Table. Reading the Periodic Table.

Average Atomic Mass. Average Atomic Mass – the weighted average of the masses of the isotopes of an element Every element is composed of several naturally.

Examples: Average Atomic Mass. Example Chlorine exists as a mixture of % chlorine-35 and % chlorine-37. Determine the average atomic mass.

Ch. 3 - Atomic Structure II. Masses of Atoms (p.75-80) Mass Number

Atomic Mass. Isotopes Reminder Yesterday we learned that the mass of all atoms of a certain element are not always the same –Some atoms may have more.

Isotopes Atoms of the same element that different mass numbers

Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons.

Average Atomic Mass The weighted average of the masses of all the naturally occurring isotopes of an element.

Quantitative Chemistry (Part 1) Isotopes Standard Atom for Mass Relative Atomic Mass Formula Mass Percentage Composition.

More about isotopes Atomic mass vs average atomic mass or atomic weight.

& Average Atomic Mass  Atoms with the same number of protons (they are the same element) but different number of neutrons.

Unit 3: Atomic Structure Atomic Mass Units (amu) and Calculating Atomic Mass.

 Atomic Number- the number of protons in the nucleus of an atom of that element  Ex: Hydrogen atoms have only one proton in the nucleus, so the atomic.

Proton, Neutron, Electron Counting Protons (p + ) are positively charged and located in the nucleus The number of protons in each atom can be found on.

Friday October 1, 2015 TO DO RIGHT NOW: 1.Get out your HW and PT 2.Copy words on page 42 3.Update your table of contents HOMEWORK Due Monday- Isotope Worksheet.

Using Isotope Data to Find a Weighted Average.  Each isotope will have two values associated with it.  Mass of Isotope  Percent Abundance (% found.

Ch. 3 - Atomic Structure II. Masses of Atoms (p.75-80)  Mass Number  Isotopes  Relative Atomic Mass  Average Atomic Mass.

…AND THE AVERAGE ATOMIC MASS Isotopes. PG 88 GENERAL- ATOMS OF THE SAME ELEMENT BUT HAVE DIFFERENT AMOUNTS OF NEUTRONS IN THE NUCLEUS PAGE 54 PRE AP ATOMS.

TAKE A …. GUIDED NOTES PAGE ATOMIC MASS W.S. ….OFF MY DESK.

Atomic Mass The Atomic Mass of Candium Lab. Atomic Mass This is the weighted average mass of the atoms in nature of that element A weighted avg mass reflects.

Atomic Mass. Masses in amu Only carbon-12 has an atomic mass exactly equal to its mass # One atomic mass unit (amu) is defined as 1/12 the mass of a carbon-12.

Isotopic Abundance SCH 3U. Atomic Mass The mass of an atom (protons, neutrons, electrons) Relative Atomic Mass: An element’s atomic mass relative to the.

Atomic Structure.  Atomic number – the number of protons in the nucleus of an atom ( ID of element )  Mass number– sum of protons and neutrons in an.

Chapter 3 Average Atomic Mass. Section 3 Counting Atoms Relative Atomic Masses The standard used by scientists to compare units of atomic mass is the.

Atomic Mass and Isotopes. Review Quiz ParticleChargeMassLocationSymbol Electron Proton Neutron.

Isotopes:Isotopes: atoms with the same number of protons but a different number of neutrons. –carbon-12 has 6 protons and 6 neutrons; –carbon-13.

Average Atomic Mass. Relative Atomic Masses  Masses of atoms (in grams) are very small, so for convenience we use relative masses.  Carbon-12 is our.

Average Atomic Mass.   atomic masses reported in periodic table represent: weighted average of masses of all naturally occurring isotopes of an element.

Isotopes. Let’s Review ProtonsNeutronsElectrons Charge +1 0 Mass 1 amu 0 Location nucleus Electron cloud.

Note: When doing calculations never clear your calculator.

Notes on Isotopes Remember Protons are (+) and Electrons are (-). Neutrons were the last subatomic particles to be discovered because they have no electrical.

Chapter 4 AVERAGE ATOMIC MASS. Atomic Mass… n The weighted average of the masses of all the naturally occurring isotopes of that element. n Is not a whole.

Notes on Isotopes Remember Protons are (+) and Electrons are (-). Neutrons were the last subatomic particles to be discovered because they have no electrical.

Atomic Structure. Subatomic Particles In the nucleus: Protons Mass  1 amu Charge = +1 Neutrons Mass  1 amu Charge = 0 In the electron cloud: Electrons.

Isotopic Abundance Pages Thinking question Why are there decimal places for atomic masses on the periodic table if protons and neutrons have amu.

Section 6.1 Atoms and Moles 1.Students will be able to describe the concept of average mass. 2.Students will be able to demonstrate how counting can be.

WEIGHTED AVERAGE MASS NUMBER: 1)The mass number on the periodic table is calculated from the weighted average of the most abundant isotopes. 2) Abundance.

This is the solution for carbon: (12) (0.9890) + (13) (0.0110) = amu mass number percent abundance % % Recall!!! carbon:

Average Atomic Mass!!!. Copper is made of two isotopes. Copper- 63 is 69.17% abundant and it has a mass of amu. Copper-65 is 30.83% abundant and.

Atomic Mass Mrs. Cook. Atomic Mass - The average relative mass of all naturally occurring isotopes of an element. relative mass – The mass of one object.

Same Element Different Atom- Isotopes All atoms of a particular element are not exactly alike. Some elements have atoms with different masses (isotopes)

Lesson 24: Isotopes An element can be identified by the # of protons it has # of neutrons can vary Neutrons add to the mass of the atom, but do not change.

Calculating Atomic Mass

II. Masses of Atoms Mass Number

Average Atomic Mass In nature, most elements are a mixture of different isotopes The mass of a sample of an element is a weighted average of all the isotopes.

Calculating Average Atomic Mass

Calculating Average Mass

Average Atomic Mass.

Ch Atomic Structure II. Masses of Atoms (p.30-31) Mass Number

Average Atomic Mass.

Atomic Structure.

Elements, Isotopes and More

How Atoms Differ Chp 4.

Atomic Structure Chemistry.

1. What are these two atoms of carbon called?

Calculating Average Atomic Mass

Atomic Math Calculations

Ch. 4 - Atomic Structure II. Masses of Atoms Ch.4 Mass Number Isotopes

1. What are these two atoms of carbon called?

Introduction to Atomic Structure

Aim: How to Calculate the Average Atomic Mass?

Section 2: Masses of Atoms

Chemistry Chapter 3 Section 3

Presentation transcript:

Atomic Masses Test Friday!

Atomic Mass is an average (decimal) An average of known isotopes for an element The atomic mass of an element is closest to the most common isotope found in nature So, since Carbon’s atomic mass is closest to 12, Carbon-12 would be the most common isotope found in nature

Isotopes and atomic mass Potassium How many protons? How many neutrons? 20 potassium atoms: 93.25% will have 20 neutrons, % will have 22 neutrons, % will have 21 neutrons 19 K

How is that weight calculated? (.9325*20) + ( *22) + ( *21) = amu a weighted average potassium atoms: 93.25% will have 20 neutrons, % will have 22 neutrons, % will have 21 neutrons All will have 19 protons, so… % will weigh 39 amu % will weigh 41 amu % will weigh 40 amu

Remember! 100% in decimal form = 1 50% =.5 35% = =.1 1% =.01.1% =.001 If in doubt, divide the percentage by 100!

Approximately 75% of the chlorine atoms found in nature have a mass of 35. The other 25% have a mass of 37. What should we report as the atomic weight for chlorine? [(.75)(35)] + [(.25)(37)] = = 35.5 The KEY is to convert the percentages to decimals correctly!

1. Suppose that there were two isotopes of Sodium. 28% of the naturally occurring sodium atoms had a mass of 22, and 72% atoms had a mass of 23. What would the average atomic weight of sodium be?

2. Suppose that there were two natural isotopes of Copper. 80% of the atoms had a mass of 63, and 20% of the atoms had a mass of 65. What would that average atomic weight of copper be?

3. Suppose that a new element (E) were discovered that existed as three natural isotopes. 25% of the atoms had a mass of 278, 38% had a mass of 281, and the remainder had a mass of 285. What would be listed as the atomic weight of this element?

Practice! Let’s do the More Average Atomic Mass worksheet.