Science A1 +2 Flashcards
(27 cards)
Dalton
Analogy: “The Billiard Ball”
- Atoms are the smallest particles of matter + are invisible\
- All atoms of the same element are identical but differ from other elements
JJ Thompson
Analogy: “The Rasin Bun”
- Atoms had tiny negatively charged particles (electrons)
- Atoms are composed of a positive matrix w/negatively charged particles
Rutherford
Analogy: “nuclear”
Stated most of an atom is empty space but contains particles with a positive nucleus and electrons orbit it (gold foil)
Bohr
Analogy: “A solar system”
-colors of light
Electrons existed in a number of energy levels (orbits)
Heisenberg + Schrodinger
Analogy: “The Cloud”
- Not possible to know the path electrons take around nucleus.
- Quantum Theory
- Mathematical
Democritus
- Ancient Greeks started the idea about atoms
- Democritus proposed that all matter was made of particles that could not be divided
- Called them Atomos (meaning invisible)
Who created the periodic table
Dmitri Mendeleev
Groups, Family, Period
Group/Family = vertical column;
-members have similar chemical properties
Period = horizontal row
Elements are classified by metals and non-metals (bold staircase)
Alkali metals, Alkali earth metals, Halogens, Noble gases
AM- Group 1 or first row on the very left (most reactive)
AEM- Group 2
Halogens - Group 17
Noble gases- Group 18 (least reactive)
Bohr Model
Neutrons and protons in the middle, electrons orbit
Atomic # = Protons (Carbon is #6, so Carbon will have 6 protons)
atomic mass is Protons + Neutrons
Isotopes
Atoms of an element that differ in a number of neutrons and atomic mass.
Ions
an atom that has gained or lost electrons or has a charge, it is an ion.
If an element loses one or more electrons to become a positively charged ion, it is called a cation.
Elements that gain electrons to become ions are known as anions.
How many electron rings would magnesium have?
3 because its found in period 3
Ionic + Molecular compounds are
When 2 or more different elements chemically
combine/bond a compound is formed.
Ionic is a Cation+Anion
Ionic compounds
Ionic is a Cation+Anion
Ionic compounds are crystalline solids at SATP (standard
atmospheric temperature and pressure), have relatively
high melting points, and are good conductors of
electricity
Molecular compounds
Molecular compounds form when 2 or more nonmetallic
atoms share electrons and bond covalently. Molecular compounds may be solid, liquid, or gaseous at SATP, but tend to have relatively low melting points and are non-conductors, with the exception of acids.
Molecular Entities
non-metals only
Molecular element
These include H2, O2, N2, P4, S8, and all the halogens.
Fluorine gas- F2
Formula for water, ammonia, and hydrogen peroxide
H2O, NH3, N2O2
Ionic + convalent bonds
= intramolecular bonds; bonds found between atoms within a molecule.
Arrhenius
suggested that acids are compounds
that contain hydrogen and can dissolve in water
to release hydrogen ions into a solution.
Buffers
Substances that can act to neutralize both acids and bases in order to minimize changes in pH
Nomenclature
Nomenclature is the process of naming chemical compounds with different names so that they can be easily identified as separate chemicals.
