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
What are the sub atomic particles of an Atom?
Proton
Electron
Neutron
Why the number of protons = number of electrons?
So the electrical charges of an atom will be neutral
Atomic number =?
number of protons
neutrons may vary because of?
Isotopes
The size of an atom may vary to the quantity of?
Shell orbit
True or False:
Fact 1- Elements in the same group have the same number of electrons in the outer shells that corresponds to their group number
True
Last energy level is also known as?
Valence shell/Valence energy level
True or False:
Fact 2- As you move down through the periods an extra electron shell is added
True
It is the horizontal arrangement of the elements
Period
True or False:
Fact 3- Most of the Elements are Metals
True
True or False:
Fact 4- (Most important) All elements in the same group have similar PROPERTIES. This is called PERIODICITY.
True
Mass of Electron is?
9.11 x 10⁻³¹ kg
Mass of Proton is?
1.67 x 10⁻²⁷ kg
Mass of Neutron is?
1.67 x 10⁻²⁷ kg
What is the magnitude charge of proton and electron?
1.67 x 10⁻¹⁹ C
The first electron shell can only hold a maximum of?
two electrons
The second electron shell can hold a maximum of?
eight electrons
The third electron shell can also hold a maximum of?
eight electrons
The fourth electron shell can also hold?
eighteen electrons
It defines the characteristics of an atom, it also defines the shapes and size of an atom
Electron
These are the tiny indivisible particles that is known as
Atoms
