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Atoms are the smallest form of elements. Chap 10-Chemistry. Names and Symbols. Elements get their names in different ways Each element has its own unique symbol Capital letter indicates a new element. Each Element is Made of A different Atom.
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Atoms are the smallest form of elements Chap 10-Chemistry
Names and Symbols • Elements get their names in different ways • Each element has its own unique symbol • Capital letter indicates a new element
Each Element is Made of A different Atom • John Dalton (Atomic Theory) said that each element is made of tiny particles called “atoms” • All of the atoms of a particular element are IDENTICAL but are different from atoms of other elements
Structure of an Atom • Subatomic Particles found in the atom
Nucleus of An Atom • Positively charged nucleus • Contains neutrons and protons • Neutrons have no charge so overall charge for nucleus is positive
Atomic Number • The IDENTITY of an atoms is determined by the number of protons in the nucleus • Atomic Number- the number of protons in the nucleus
Mass Number • TOTAL number of Protons and Neutrons in the atom’s nucleus
Atomic Number Examples(page 28) Atomic Number Atomic Mass Atomic number equals the number of protons or electrons Atomic mass equals the number of neutrons + protons.
Atom Model Rubric- Due Wed 9/7Present to class- big grade ! • Atom correctly modeled • Correct number of subatomic particles • Correct location of subatomic particles • Includes Key • Items used to demonstrate creativity (not just colored on the page) • Atom square includes atomic mass, number and symbol • Correct energy levels and electrons in each
Template- Must be in your notebook (atomic structure) general picture
More Examples page 34- drawing atoms with Bohr Models • Boron Neon
More Examples page 34- drawing atoms with Bohr Models • Helium Carbon
Tonight’s HW • Finish rest of page 34 and 35 • Use your periodic table to find out if the element is a solid, liquid or gas ! • We’ll grade and check it tomorrow
Periodic Table • Dmitri Mendeleev- 1869 • Shows a periodic or repeating pattern of properties of the elements • Gaps- new elements discovered would complete the chart
Periodic table organizes atoms of the elements by properties and atomic number • Elements arranged by atomic number (number of protons) • Each square gives specific information about the atoms of an element • Number at top of the square, # of protons in the nucleus of that atom • Chemical Symbol- abbreviation for element’s name; contains one or two letters
Reading the Periodic Table • Some elements that have not been named are given a temporary 3 letter symbol • Name of the element is written below the symbol • The number below the symbol tells the average atomic mass of all the elements
Reading the Periodic Table • The color of the element’s symbol tells the physical state at room temperature. • White letters like H (hydrogen) indicate a gas • Blue letters indicate a liquid • Black letters indicate a solid
Reading the Periodic Table • Background colors of the square indicates whether the element is a metal, non-metal or metalloid.
Group • Each column (top to bottom) is called a group. • Elements in a group share similar chemical and physical properties • Groups are read from top to bottom • The groups are labeled at the top of the column • Group are also called “FAMILIES”
Period • Each row of the periodic table is called a period • Read from left to right • Horizontal row
Periodic Table has distinct regions • Three main regions • Metals on the left • Nonmetals on the right (except hydrogen) • Metalloid between
Reactivity • The element’s location on the table tells us how reactive an element is • Reactive- how likely an element is to undergo a chemical change • Atoms in groups 1 and 17 are the most reactive • Elements in group 18 are the least reactive
Bohr Model- Where electrons are found • Energy Superhighway Can hold 18 electrons Energy Freeway Can hold 8 electrons Energy Street Can hold 2 electrons
Metals • Most elements are metals • Metals conduct electricity and heat well and have a shiny appearance • Can be shaped easily by pounding, bending, or being drawn into a long wire
Reactive Metals • Group 1 • Alkali metals • Ex: Sodium and Potassium • Group 2 • Alkali earth metals • Less reactive
Isotopes • Atoms of certain elements ALWAYS have the same number of protons, may not always have the same number of NEUTRONS. • Not all atoms of an element have the same MASS NUMBER • Ex: Chlorine- some have 17 protons and 18 neutrons, other chlorine atoms have 20 neutrons
Ions-formed when an atom loses or gains one or more electrons • Sodium – 11 electrons, loses an electron • Chlorine- 17 electrons, gains an electron