Atomic Structure Flashcards
- Developed the idea of atoms
- Pounded up materials in pestle and mortar until he had reduced them to smaller particles - ‘Atomos
Democritus
neutral same mass as proton (“1”)
Neutron
positive same mass as neutron (“1”)
Proton
negative mass nearly nothing
Electron
What does the Dalton’s Atomic Theory states?
- All matter is made up of tiny, indivisible particles called atoms.
- All atoms of the same element have the same chemical properties. Conversely, atoms of different elements have different chemical properties.
- Compounds are formed by the chemical combination of two or more different kinds of atoms.
- A molecule is a tightly bound combination of two or more atoms that act as a single unit.
- Discovered by Erwin Schrodinger and Werner Heisenberg.
- Atom consists of a dense nucleus and many protons and neutrons and is surrounded by electrons, but they all have different energy levels, and different charges.
1920s Electron Cloud Model
Matter can be neither created nor destroyed
The Law of Conservation of Mass
- The total mass of matter at the end of the experiment was exactly the same as that at the beginning.
- Dalton’s theory explained: If all matter consists of indestructible atoms, then any chemical reaction changes the attachments between atoms but does not destroy the atoms themselves.
The Law of Conservation of Mass
True or False:
Any compound is always made of elements in the same proportion by mass
True
True or False:
In Dalton’s Theory, If H₂O molecule consists of 1 atom of O and 2 atoms of H and if O atom has a mass 16 times that of a H atom, then the mass ratio of these 2 elements must always be 8 to 1
True
Helium and Neon - have single atom
Monoatomic elements
Gases that exist in nature; each has 2 atoms joined together by chemical bond
Diatomic elements
proposed that electrons outside the nucleus are “quantized”
N. Bohr
neutron and proton (combined) is also called?
Nucleons
True or False:
number of protons = number of electrons
True
