Chap 3 Flashcards
The four key features of Dalton’s atomic theory
- Elements are made of tiny, indivisible particles called atoms
- Atoms combine/can join together in whole number ratios (to form compounds).
- Atoms of each element are unique
- Atoms are unchanged in chemical reactions.
The atom is
The fundamental unit of matter.
Each element is composed of a different type of atom, which gives each element its unique properties.
(‘atom’ derived from ‘atomos’, meaning: “indivisible”)
The Law of Conservation of Mass (Antoine Lavoisier, born 1794)
States: “In chemical reactions, matter is neither created nor destroyed”
The three foundational ideas:
- All mater is composed of atoms
- The atoms of each element have unique characteristics and properties
- -In chemical reactions. atoms are not changed, but combine in whole number ratios to form compounds.
Can we see atoms?
No. Atoms are too small to be seen with a naked eye, or even a microscope.
Scientists use x-ray crystallography to visualize the arrangement of atoms.
The Periodic table arrangement
Rows(horizontal)- called “periods”
Columns(vertical)- called “groups” or “families”
Main group elements locations
The two side blocks (Columns 1A-2A (1&2) and 3A-8A(13-18))
Location of the transition & inner transition elements
Block between the main group elements blocks (columns 3-12)
Subatomic particles
Particles that make up atoms
Location of Alkali Metals
Collum 1A
Location of Alkaline earth metals
Collum 2A
Location of Halogens
Collum 7A
Location of Noble Gasses
Collum 8A
Mass number =
protons + neutrons
Atomic Theory
a theory describing matter in terms of fundamental units, atoms
Atomic mass unit (u or amu)
A unit of mass equal to 1.66x10^-27kg
Charge
a characteristic property of subatomic particles that affects how particles interact with each other
Electron
A negatively charged sub-atomic particle. the electrons occupy the space around the nucleus.
Nucleus
The tiny, dense center of an atom. The nucleus contains protons and neutrons.
Electron cloud
the space around the nucleus. Accounts for nearly the entire volume of the atom
Atomic number
The number of protons in an atom, also the number of electrons in a neutral atom
What are six evens in uncovering atomic structure?
1) Volta’s electrochemical cell
2) Dalton’s atomic theory
3) Mendeleev’s periodic table
4) Thomson discovers the electron
5) Plum pudding model
6) Rutherford proposes the nucleus
Isotopes
Atoms that have the same atomic number but different mass numbers
Plum pudding model
Negative electrons spread throughout a positive material
Net charge(total charge/ overall charge?)
= #Protons - #electrons
Bohr model
Electrons orbit the nucleus like planets orbit the sun
Quantam model
Electrons behave both as particles and waves
Atoms gain or loose electrons to form
Ions
Ion
atom or group of atoms with an overall charge
average atomic mass
weighted average of the different isotopes of an element
