Chemistry Patterns Flashcards
(56 cards)
What are atoms?
The smallest unit of matter.
What was john dalton’s model of the atom?
“billard ball model”
the atom is a ball-like structure
What was john dalton’s atomic theory?
- All atoms are indivisible
- atoms of the same element are identical
- different elements have different types of atoms
- all matter is composed of atoms
what were the benefits and limitations of john dalton’s theory
- identified all matter is made of atoms
- didn’t identify subatomic particles or nucleus
what was jj thomsons atomic model?
“plum pudding model”
Negatively charged particles in a spherical cloud of positive charge.
What was jj thomsons atomic theory
- atoms contain subatomic particles that are negatively charged.
- he named them corpscules
what were the benefits and limitations to jj thomson’s theory?
- didn’t identify nucleus
- identified electrons
what was ernest rutherford’s atomic model?
“nuclear model”
positive charge contained in the center with electrons orbiting.
benefits and limitations to rutherford’s model?
- identified an atom was made up of empty space
- identified the nucleus
-failed to explain the stability of an atom
*rutherford’s theory of atoms orbiting the nucleus failed to address that any charged particle in acceleration (which includes an electron in circular orbit) should emit electromagnetic radiation. As the electron emits this radiation, it would lose energy. the loss of energy should cause it to spiral into the nucleus and collapse it.
what was neil bohr’s atomic model?
“planetary model”
The electrons orbit the nucleus at fixed energies.
bohr’s theory?
Based on quantum theory that some physical quantities only take discrete values.
benefits and limitations to bohr’s model?
- explained the stability of an electron
- it failed to make correct predictions of large-sized atoms and explain the spectrum of atoms having only two electrons, such as the helium atom. The primary focus was on hydrogen, another limitation of the Bohr model.
- violates heisenberg’s uncertainty principle that we cannot know both the position and speed of a particle, such as a photon or electron, with perfect accuracy
where are electrons found?
orbiting the nucleus
where are protons and electrons
in the nucleus
explain the charge and mass of protons, neutrons and electrons
protons: positive charge, 1 mass unit
neutrons: no charge, 1 mass unit
electrons: negative charge, negligible mass
where is the atomic number on an element?
at the top of the box
where is the atomic mass on an element?
the decimal below the chemical symbol
where is the chemical on an element?
the big letters
explain groups and periods.
groups are the collums, and periods are the rows.
how to find the no. of
*valence electrons
*protons
the group no. is the no. of valence electrons.
The atomic number is the no. of protons.
how to find the no. of neutrons?
subtract the number of protons, or atomic number, from the mass number
what are physical properties?
properties that describe the physical characteristics of a substance, not how it behaves chemically.
examples of physical properties
- solubility
- viscosity
- ductilibility
- malleability
- boiling point
what are chemical properties?
properties of a substance that describe how that substance’s chemical composition will change.
