Presentation is loading. Please wait.

Presentation is loading. Please wait.

ARE ALL ATOMS OF THE SAME ELEMENT IDENTICAL?

Published byKevin Sullivan Modified over 5 years ago

Similar presentations

Presentation on theme: "ARE ALL ATOMS OF THE SAME ELEMENT IDENTICAL?"— Presentation transcript:

1 ARE ALL ATOMS OF THE SAME ELEMENT IDENTICAL?
Isotopes and Average atomic mass

2 Isotopes Dalton was wrong about all elements of the same type being identical Atoms of the same element can have different numbers of neutrons. Thus, different mass numbers. These are called isotopes.

3 B. Isotopes Mass # Atomic #
Atoms of the same element with different mass numbers. Nuclear symbol: Mass # Atomic # Hyphen notation: carbon-12 C. Johannesson

4 Naming Isotopes Using Hyphen Notation
We can also put the mass number after the name of the element: carbon-12 carbon-14 uranium-235

5 Isotopes are atoms of the same element having different masses, due to varying numbers of neutrons.
Protons Electrons Neutrons Nucleus Hydrogen–1 (protium) 1 Hydrogen-2 (deuterium) Hydrogen-3 (tritium) 2

6 B. Isotopes Chlorine-37 17 37 20 atomic #: mass #: # of protons:
# of electrons: # of neutrons: 17 37 20 C. Johannesson

7 Isotopes Elements occur in nature as mixtures of isotopes.
Isotopes are atoms of the same element that differ in the number of neutrons.

8 Atomic Mass How heavy is an atom of oxygen?
It depends, because there are different kinds of oxygen atoms. We are more concerned with the average atomic mass. This is based on the abundance (percentage) of each variety of that element in nature. We don’t use grams for this mass because the numbers would be too small.

9 Measuring Atomic Mass Instead of grams, the unit we use is the Atomic Mass Unit (amu) It is defined as one-twelfth the mass of a carbon-12 atom. Carbon-12 chosen because of its isotope purity. Each isotope has its own atomic mass, thus we determine the average from percent abundance.

10 D. Average Atomic Mass Avg. Atomic Mass
weighted average of all isotopes on the Periodic Table round to 2 decimal places Avg. Atomic Mass C. Johannesson

11 D. Average Atomic Mass EX: Calculate the avg. atomic mass of oxygen if its abundance in nature is 99.76% 16O, % 17O, and 0.20% 18O. Avg. Atomic Mass 16.00 amu C. Johannesson

12 D. Average Atomic Mass EX: Find chlorine’s average atomic mass if approximately 8 of every 10 atoms are chlorine- 35 and 2 are chlorine-37. Avg. Atomic Mass 35.40 amu C. Johannesson

13 Composition of the nucleus
Atomic Masses Atomic mass is the average of all the naturally occurring isotopes of that element. Isotope Symbol Composition of the nucleus % in nature Carbon-12 12C 6 protons 6 neutrons 98.89% Carbon-13 13C 7 neutrons 1.11% Carbon-14 14C 8 neutrons <0.01% Carbon =

Download ppt "ARE ALL ATOMS OF THE SAME ELEMENT IDENTICAL?"

Similar presentations

Atomic Structure. What is an atom? Atom: the smallest unit of matter that retains the identity of the substance.

Atomic Structure. What is an atom? Atom: the smallest unit of matter that retains the identity of the substance.
Atomic Structure Nucleus – contains protons and neutrons

Atomic Structure Nucleus – contains protons and neutrons
OF PROTONS, NEUTRONS AND ELECTRONS IN AN ATOM

OF PROTONS, NEUTRONS AND ELECTRONS IN AN ATOM
Wake-up 1.Explain the relationship between the following: atomic number, mass number, protons, neutrons, and electrons. 2.How do you find the number of.

Wake-up 1.Explain the relationship between the following: atomic number, mass number, protons, neutrons, and electrons. 2.How do you find the number of.
Dalton was proved incorrect and his theory was modified

Dalton was proved incorrect and his theory was modified
Counting Atoms.

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

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

Atomic Structure I. Subatomic Particles.
Isotopes Atoms of the same element that different mass numbers

Isotopes Atoms of the same element that different mass numbers
Topic #7. Dalton was wrong about all elements of the same type being identical Atoms of the same element can have different mass numbers. ISOTOPES.

Topic #7. Dalton was wrong about all elements of the same type being identical Atoms of the same element can have different mass numbers. ISOTOPES.
Isotopes Dalton was wrong about all elements of the same type being identical Atoms of the same element can have different numbers of neutrons. Thus, different.

Isotopes Dalton was wrong about all elements of the same type being identical Atoms of the same element can have different numbers of neutrons. Thus, different.
Isotopes  Atoms with the same number of protons but different numbers of neutrons  Ex) Carbon 12 vs. Carbon 14  These atoms have a different mass 

Isotopes  Atoms with the same number of protons but different numbers of neutrons  Ex) Carbon 12 vs. Carbon 14  These atoms have a different 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.

 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.
Subatomic Particles. Atomic Particles ParticleChargeMass (kg)Location Electron9.109 x 10 -31 Electron cloud Proton+11.673 x 10 -27 Nucleus Neutron01.675.

Subatomic Particles. Atomic Particles ParticleChargeMass (kg)Location Electron9.109 x Electron cloud Proton x Nucleus Neutron
Isotopes Atoms of the same element with different mass numbers. Mass # Atomic # Nuclear symbol: Hyphen notation: carbon-12 Courtesy Christy Johannesson.

Isotopes Atoms of the same element with different mass numbers. Mass # Atomic # Nuclear symbol: Hyphen notation: carbon-12 Courtesy Christy Johannesson.
Chapter 4 “Atomic Structure”. “Animal Style” Atom.

Chapter 4 “Atomic Structure”. “Animal Style” Atom.
Ch. 3 - Atomic Structure II. Masses of Atoms (p.75-80)  Mass Number  Isotopes  Relative Atomic Mass  Average Atomic Mass.

Ch. 3 - Atomic Structure II. Masses of Atoms (p.75-80)  Mass Number  Isotopes  Relative Atomic Mass  Average Atomic Mass.
C. Johannesson Atomic Structure. Structure of the Atom  Protons- Positively charged particles in the nucleus  Neutrons-neutrally charged particles in.

C. Johannesson Atomic Structure. Structure of the Atom  Protons- Positively charged particles in the nucleus  Neutrons-neutrally charged particles in.
Wake-up Explain the relationship between the following: atomic number, mass number, protons, neutrons, and electrons. How do you find the number of electrons.

Wake-up Explain the relationship between the following: atomic number, mass number, protons, neutrons, and electrons. How do you find the number of electrons.
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.

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.

Similar presentations

Ads by Google