Gen Chem

• Atom started when democritus stated that all matter consist of tiny particles
• Democritus called these tiny particles as atomos which means indivisible
• Electros was discovered by JJ thomson
• Protons were discovered by ernest rutherford
• Neutrons were discovered by James chadwick
• protons are positively charged and founf at the nucleus
• neutrons are neutral and found at the nucleus
• Electrons are negatively charged and more around the nucleus
• the concept of atomism describes an atom as both indivisible and indestructible particle
• Thales thought it was water
• Anaximenes thought it was air
• Heraclitus thought it was fire
• Empedocles thought it was earth
• John Dalton proposes the solid sphere model
• Joseph john Thomson proposes the plum pudding by using the cathode ray tube and the electromagnetic theory to determine the ratio of electric charge to the mass of the individual negatively charged of particle
• Atoms are electrically neutral
• atoms contain electron
• Electrons are negatively charged particles that are embedded on the body of the atom according to the plum pudding mode
• Ernest Rutherford proposes the nuclear model in 1911 with his gold foil experiment or geiger marsden
• Atoms are the building block of matter
• according to the nuclear model, the nucleus is at the center of the atom and this is where the mass of the atom is concentrated
• protons are found in the nucleus while electrons are the smaller particle around the nucleus
• Niels Bohr proposes the planetary model
• niels bohr propose that electrons moved in fixed orbits
• valence electrons are the outermost electrons
• Chemical bonds are the result of either the transfer or sharing of electrons between two atoms
• Chemical bonds can be classified as Ionic, Covalent, or Metallic
• ion are charged particles
• If atoms lose electrons, they become positive ions, or cations. If atoms gain electrons, they become negative ions, or anions.
• cation are positively charged particle
• anion are negatively charged particle
• Ionic bonds are formed through the transfer of electrons from Metal to nonmetal
• Metallic bonds are formed through the sharing of electrons between two metallic atoms
• Covalent bonding are formed through the sharing of an electron between two nonmetal atoms
• metal to nonmetal is ionic
• nonmetal to nonmetal is covalent
• metal to metal is metallic
• electronegativity refers to the atoms ability to attract electrons in a chemicla bond to itself
• polar covalent bond occurs when atoms are shared unequally in a covalent bond.
• Nonpolar covalent bond is a type of chemical bond that is formed when electrons are shared equally