unit 4.1-4.2

who was the first person to use the term atom (Atomos: meaning indivisible).

• Democritus. ~450 BC.

• John Dalton. 1803

• Ernest Rutherford. 1909.

• J. J. Thomson. 1896.

The Nucleus

• The central part of an atom contains protons and neutrons

• particles with no charge in the nucleus of an atom

• - Positively charged particles in the nucleus of an atom

• Very small negatively charged particles in an atom

The Electrons

• Positively charged particles in the nucleus of an atom

• particles with no charge in the nucleus of an atom

• The central part of an atom contains protons and neutrons

• Very small negatively charged particles in an atom

The Protons

• particles with no charge in the nucleus of an atom

• Very small negatively charged particles in an atom

• Positively charged particles in the nucleus of an atom

• The central part of an atom contains protons and neutrons

The Neutrons

• Positively charged particles in the nucleus of an atom

• The central part of an atom contains protons and neutrons

• particles with no charge in the nucleus of an atom

• Very small negatively charged particles in an atom

What is the current model of atom

• Wave mechanical model.

• Rutherford nuclear model

• Bohr model

• Electron cloud model

who was the first to adapt Democritus’ theory into the first modern atomic model

• John Dalton.

• J. J. Thomson.

• Robert Millikan.

• Ernest Rutherford.

Which atom model failed?

• Bohr model

• Rutherford nuclear model

• Wave mechanical model.

• Dalton's Model of the Atom.

What is chromatogram?

• the pattern of spots produced during chromatography

• a technique used to seperate soluble substances

• the ratio of the solute's distance travelled to the solvent's distance travelled.

• substances dissolves to form a solution

Rf value

• the pattern of spots produced during chromatography

• the ratio of the solute's distance travelled to the solvent's distance travelled

• Chromatography synanom

• when a soluble substance becomes a solution