Atomic Structure Matter Anything that has a mass

Atomic Structure

Matter • Anything that has a mass and a volume • Matter is made up of different kinds of atoms.

• An _____ is the smallest particle of an element that has the chemical properties of the element. Copper atoms on silica surface. Distance across = 1. 8 nanometer (1. 8 x 10 -9 m)

• Atoms are the smallest unit of matter that is still that kind of matter. They are too small to be seen without very powerful microscopes. • Everything is made of atoms • There are over 100 types of atoms. • Examples: oxygen, carbon, nitrogen

• Atoms have mass and take up space. • Atoms are always in motion. The state of matter of a substance is determined by how much energy the atoms have…how much they’re moving.

• The building blocks of Matter • Consists of Protons (+), Electrons (-), and Neutrons (N). • Consists of only one kind of atom, • Cannot be broken down into a simpler type of matter by either physical or chemical means • Can exist as either atoms or molecules. Images are from http: //www. chem 4 kids. com

Elements l Pure substances that cannot be separated into different substances by ordinary processes l Are the building blocks of matter l 112 elements known today Examples: carbon gold calcium • Elements are made up of all of the same kind of atom Lecture. PLUS Timberlake 7

The Language of Chemistry • CHEMICAL ELEMENTS - – pure substances that cannot be decomposed by ordinary means to other substances. Aluminum Sodium Bromine

9 Elements Lecture. PLUS Timberlake l. Pure substances that cannot be separated into different substances by ordinary processes l. Are the building blocks of matter l 112 elements known today Examples: carbon gold calcium • Elements are made up of all of the same kind of atom

Subatomic Particles • Proton • Electron • Neutron

Protons • have a positive charge (+) • found in the nucleus • have mass ++ ++

Neutrons • have no charge (o) • found in nucleus • have mass o oo+ +o+

Electrons • have a negative charge (-) • whirl around nucleus • have almost no mass o oo+ +o+ -

Subatomic Particles • Protons and electrons are the only particles that have a charge. • Protons and neutrons have essentially the same mass. • The mass of an electron is so small we ignore it.

http: //www. eskom. co. za/nuclear_energy/fuel. html

See more diagrams at: http: //www. bmb. psu. edu/courses/bisci 004 a/chem/basechem. htm

http: //www. bmb. psu. edu/courses/bisci 004 a/chem/atoms. jpg

Draw a diagram showing the charges of each part of the atom.

ATOM COMPOSITION The atom is mostly empty space • protons and neutrons in the nucleus. • the number of electrons is equal to the number of protons. • electrons in space around the nucleus. • extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean has teaspoons of water.

ATOMIC COMPOSITION • Protons (p+) – + electrical charge – relative mass = 1. 007 atomic mass units (amu) but we can round to 1 • Electrons (e-) negative electrical charge – relative mass = 0. 0005 amu but we can round to 0 – • Neutrons (no) – no electrical charge – mass = 1. 009 amu but we can round to 1

Atomic Number • is the # of protons in nucleus of an atom • it identifies the element • found above the symbol on the periodic table 1 H Hydrogen 1. 00

Atomic Mass • tells the mass of the nucleus • is the sum of the protons and neutrons • found under the symbol on the periodic table 1 H Hydrogen 1. 00

Electrons • # of electrons = # of protons in an uncharged atom • electron cloud- entire space that the electrons occupy

Finding # of Neutrons • Subtract the atomic number from the rounded atomic mass

Isotopes • Are atoms of the same element that have a different number of neutrons • These are what cause the atomic mass to be an average

Atomic Number All atoms of the same element have the same number of protons in the nucleus 13 Al 26. 981 Atomic number Chemical symbol AVERAGE Atomic Mass

Nucleus • The nucleus is the center of an atom. • Made of protons and neutrons. • The nucleus contains the atom's mass.

Protons • positively charged particles • found in the nucleus. • Have mass = 1. 007 atomic mass units (amu) but we can round to 1

Neutrons • Uncharged particles • Found in the nucleus. • Mass = 1. 009 amu but we can round to 1

Electrons • Negatively charged particles • Surround the atom's nucleus. • Chemical reactions involve sharing or exchanging electrons. • mass = 0. 0005 amu but we can round to 0

Describe Isotope Atoms that have the same number of protons but different numbers of neutrons

Describe Isotope Example: http: //education. jlab. org/glossary/isotope. html

Isotopes • Are atoms of the same element that have a different number of neutrons • These are what cause the atomic mass to be an average

What is the Electron Cloud Model? Model of the atom pictures the electrons moving around the nucleus in a region called an electron cloud. The electron cloud is a cloud of varying density surrounding the nucleus. The varying density shows where an electron is more or less likely to be. Atoms with electrons in higher energy levels have additional electron clouds of different shapes that also show where those electrons are likely to be. For more information, click here: http: //regentsprep. org/Regents/physics/phys 05/catomodel/cloud. htm

What is the Electron Cloud Model? Diagram 1:

What is the Electron Cloud Model? Diagram 2:

Periodic Table Atomic number 6 Element’s symbol C Element’s name Carbon Atomic mass 12. 011

Chemical Symbols • abbreviations for elements • 1 or 2 letters; 1 st is capitalized and 2 nd is lower case • ex- Aluminum = Al not AL

Atomic Number • is the # of protons in nucleus of an atom • it identifies the element • # of protons = # of electrons in uncharged atom 1 H Hydrogen 1. 00

Atomic Number All atoms of the same element have the same number of protons in the nucleus 13 Al 26. 981 Atomic number Atom symbol AVERAGE Atomic Mass

Atomic Mass • tells the mass of the nucleus • is the sum of the protons and neutrons • found under the symbol on the periodic table 1 H Hydrogen 1. 00

Atomic Mass • C atom with 6 protons and 6 neutrons • = 12 atomic mass units • Mass Number = # protons + # neutrons • NOT on the periodic table…(it is the AVERAGE atomic mass on the table) • A boron atom can have 5 p + 5 n = 10 amu 10 5 B

Electrons • # of electrons = # of protons in an uncharged atom • electron cloud- entire space that the electrons occupy – 1 st energy level is full with 2 – 2 nd energy level is full with 8 – 3 rd energy level is full at 8, but can hold up to 18 in all the sublevels

Finding # of Neutrons • Subtract the atomic number from the rounded atomic mass