Introduction to the Atom • Modern Atomic Theory • Subatomic Particles • Isotopes • Ions • Essential Standards and objectives: • 1.1.1 Analyze the structure of atoms, isotopes, and ions. • 1.1.2 Analyze an atom in terms of the location of electrons. • 1.1.3Explain the emission of electromagnetic radiation in spectral form in terms • of the Bohr model. • 1.1.4 Explain the process of radioactive decay using nuclear equations and half-life. • 2.2.5 Analyze quantitatively the composition of a substance. (Introduction to moles)
The Atom: Smallest particle of an element that retains the chemical properties of the element. Essential Questions: What is an atom? What is its structure? What determines properties of an element?
PHET Build an Atom • Use this in the search window • Share a computer with a partner • Individual work (write your answers on a separate paper) • http://phet.colorado.edu/en/simulation/build-an-atom
Explain: How does this graphic demonstrate the characteristics of an atom? Make sure that you include each graphic (portions) in your explanation
Reading: Cornell notes Essential questions: What are the characteristics of an atom? In your notes: address both individual atoms and atoms of an element
Modern Atomic Theory • All matter: • Atoms of a given element: • Atoms cannot be created nor destroyed in: • In chemical reactions, atoms are
Atomic Theory (cont.) • To form compounds: Law of Definite Proportions Law of Multiple Proportions
Summary Table: Atomic Structure- Subatomic Particles SubatomicLocationChargeMassImportance ParticleAMU
Designation of Atomic Structure • Atomic number (Z): • On the Periodic Table: • Mass number (A): • On the Periodic Table:
Representing atoms • Information from symbols and the Periodic Table
What does this symbol tell us? Protons: Neutrons: Electrons:
20 Ca 40.08 Designations for the Atomic Structure Atomic number (Z): • On the Symbol • On the Periodic Table Mass number (A): • On the Symbol • On the Periodic Table
Review: What is Z? What is A? Determine the number of protons, neutrons, and electrons. 31 Ga Gallium 69.72 32 Ge Germanium 72.61
Periodic Table: an Important Tool in Chemistry but no set rules for what is included and where 16 S 32.06 S 16 32.06 How can we tell which is the atomic number and the mass number?
AMU = relative measurement and used for comparison Atomic Mass Unit AMU The “amu” is defined as one twelfth of the mass of an atom of carbon-12 (with 6 protons and 6 neutrons) and has a value of 1.660538921×10−27kg.
Organization of the Periodic Table • Columns – Groups • All the elements have similar chemical and physical properties • All will chemically react in a similar way • Names of groups • Rows – Periods • Elements have same number of energy levels
Isotopes: • Atoms of an element with different masses • Naturally occurring • Some are stable and some are radioactive (unstable) • Isotopes of an element have the same number of ___________ and a different number of ______________.
Identifying Isotopes • Isotope Notation 1. 2. On the Periodic Table, the number with the Decimal point is:
Atomic Mass • Weighted Average Mass of isotopes • Based on the percentage of each isotope present.
Grades are often computed using a weighted average. • Suppose that homework counts 10%, quizzes 20%, Labs 10% and tests 60%. • If: homework grade is 92 quiz grade is 68 lab grade is 88 test grade is 81 What’s the overall grade?
Practice • Atomic Structure • Identify the number of proton, neutron, & electrons of an atom of a specific element • Rounding the atomic mass on the Periodic Table gives the mass of the most common isotope • Atomic Number & Isotopes • Correct symbol: A & Z • Complete the table • Complete the questions.
Practice: • Find the Average Atomic Mass • Nucleus of each atom is represented • Graphic below #4 - explains #5-7 • Isotopes: Atomic Number & Mass Number • Determine based on the chart – not the PT • 2 Isotope notations • Element – A (X-A) A ZX
Here are several models of the atom as they were developed in history: ............ ...... ................ Development of the Modern Atomic Model
Quantum Model • Electron Cloud model of the atom
Bohr Model & the Periodic Table Making Conclusions Compare and Contrast • Why are elements placed in a group (column)? • Why are elements placed in a period (row?)
Changing An Atom Changing an Atom
Ions • Atoms can lose or gain electrons when bonding to make ionic compounds • We keep track of the number of electrons that can be lost or gained with oxidation numbers (also known as charges) • Ions are charged particles –when an atom has too many or too few electrons to be neutral • No change to the nucleus • Proton and neutrons stay the same number.
Ions – Charged Particles 7. When atoms of elements form ions (__________ __________, they must either __________ or _______ valence electrons. Gain/lose? ChargeIon type? Metals Non-metals
Why are ions important? The ___________________ charged particles are like a magnet. Therefore, they are strongly held together in an ______________ _____________ forming an _____ ________________.
Ions Lithium atom - Lithium ion Ion Symbol p+ p+ nº nº e- e- Fluorine atomFluorine ion p+ p+ nº nº e- e-
Ions and ChargeNet electric charge Note change 8
Ions and Charges for Representative Elements (Oxidation number keep track of electrons)