atoms basic building blocks of matter. –atoms make up everything (that has mass and takes up...
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ATOMS
• Basic building blocks of matter.– Atoms make up everything (that has mass
and takes up space).
Atomic Structure
• Protons – positively charged particles inside the nucleus.
• Neutrons – neutral particles inside the nucleus that have No charge.
• Electrons – negatively charged particles in atoms found around the nucleus.
A = P = E M – A = N
•Atomic # = Protons = Electrons
•Mass – Atomic # = Neutrons
Atomic Particle Size
Atomic Mass Unit - amu
• Unit of measurement for the mass of subatomic particles.– 1 amu = 1.7 X 10 -24 They are TINY!!!
• .000000000000000000000017 grams
– Proton = 1 amu– Neutrons = 1 amu– Electrons = almost zero (TINIEST particle with
the least mass)– Most mass is in the nucleus with protons and
neutrons– Otherwise atoms are mostly EMPTY SPACE
Atomic Number
• The number of protons inside the nucleus of the atom.
• Determines the element.
• Atoms have no charge because the # of protons (+ charge) is = to the # of electrons (- charge).
Mass Number/Atomic
Mass• The total number of protons and
neutrons in an atoms nucleus.
• Protons + Neutrons = Mass Number
• Notice how massive the nucleus is compared to the rest of the atom
Atomic Mass
• The weighted average of the masses of all the naturally occurring isotopes of an element.
• Average of Protons + Neutrons of all an elements Isotopes = Atomic Mass
Electron Cloud
• Area around the nucleus where electrons are arranged.
• Energy Levels – Levels within the electron cloud that hold a specific # of electrons.
– 1st level - 2 electrons– 2nd level - up to 8 electrons– 3rd level – up to 8 or 18
Valence Electrons
• The electrons in the outermost energy level (electron cloud).
• What element is this?
• How many valence electrons does it have?
ELEMENTS
• All the atoms that make up our universe• Identified by the atomic # (# of protons)
3 Main Groups on the Periodic Table
Metals
• Make up most of the elements• All solid except Mercury• Has luster (shiny)• Good conductors of heat and
electricity• Malleable – made into different
shapes• Ductile – made into wires
Metals
Nonmetals
• Usually gases or brittle solids• Poor conductors of heat and
electricity• Right side of the periodic table• Only 17 nonmetals
Metalloids
• Called Semi-metals• Share properties of both metals and
nonmetals
Groups/Families
• Columns of the periodic table
• Each element has the same # of valence electrons
• The elements share similar chemical and physical properties.
• They are each part of the same “family”
Periods
• 7 rows on the periodic table
• Consist of elements with the same number of electron levels.
Alkali Metals
• Group #1• All metals• 1 Valence Electron• Very reactive• Most reactive – the
only need to lose 1 valence electron in chemical bonds
Alkaline-Earth Metals
• Group #2• All Metals• 2 Valence
Electrons• Very reactive but
less than group #1.• Only have to lose 2
valence electrons in chemical bonds
Valence Electrons
• Group 1 – all elements have 1 valence electron
• Group 2 – all elements have 2 valence electrons
Transition Metals
• Groups # 3-12
• All metals
• 1 or 2 valence electrons
• Less reactive than group #2
• Also contains lanthanide and actinide series
Groups # 13-16
• Elements change from metals to nonmetals and include the metalloids.
• Atoms have 10 fewer valence electrons than the group #.
• Boron Group #13 - 3 valence electrons• Carbon Group #14 - 4 valence electrons• Nitrogen Group #15 - 5 valence electrons• Oxygen Group #16 - 6 valence electrons
Halogens
• Group 17• All nonmetals• 7 valence electrons• Very reactive
– Only need to gain 1 more electron for a total of 8!
Noble Gases/Inert Gases
• Group # 18• All nonmetals• 8 valence electrons
- except helium only has 2.
• Unreactive– Have a full outer
electron level– 2 on the 1st level– 8 on the 2nd level
Hydrogen stands alone
1 valence electronVery reactiveColorless, odorless
gas at room temperature.
Low densityReacts explosively
with Oxygen