Presentation on theme: "SUBATOMIC PARTICLES. REVIEW ATOMS Atom An atom is the smallest particle of an element that still has the properties of that element 50 million atoms,"— Presentation transcript:
REVIEW ATOMS Atom An atom is the smallest particle of an element that still has the properties of that element 50 million atoms, lined up end-to-end = 1 cm An atom = proton(s) + neutron(s) + electron(s) The Greek root for the word atom, "atomon," means "that which cannot be divided.”
The structure of the atom ELECTRON – negative, mass nearly nothing PROTON – positive, same mass as neutron (“1”) NEUTRON – neutral, same mass as proton (“1”) The Ancient Greeks used to believe that everything was made up of very small particles. Some experiments in 1808 proved this and called these particles ATOMS:
The Atom: Nucleus Electron Shell or Orbit
The Atom Hydrogen: Proton Electron Hydrogen has one proton, one electron and NO neutrons
The Atom Sodium Protons Neutrons Electrons Sodium has eleven electrons, eleven protons and twelve neutrons. Valence Shell
Atomic Theory: Atoms are made up of smaller particles known as sub-atomic particles. The nucleus is at the center of an atom. The nucleus is composed of protons and neutrons. Electrons exist in the space surrounding the nucleus. # of protons = # of electrons in every atom Nuclear charge = charge on the nucleus = # of protons Atomic number = # of protons = # of electrons See page 170 Name Symbo l ChargeLocationRelative Mass Protonp1+nucleus1836 Neutronn0nucleus1836 Electrone1– area surrounding the nucleus 1
Mass and atomic number ParticleRelative MassRelative Charge Proton11 Neutron10 Electron0 MASS NUMBER = number of protons + number of neutrons SYMBOL ATOMIC NUMBER = number of protons (obviously)
Subatomic Particles 1 H Hydrogen Element symbol Element name Atomic mass Atomic number Group 1 Period 1 Atoms are split into subatomic particles (electrons, neutrons, protons) Nucleons are particles of the nucleus of the atom These include protons (1 +), neutrons (no charge) Number of protons in element is the atomic number (ie H has 1 proton) Electrons have charge (1-) are located outside of nucleus Neutral atom, their number of electrons equals atomic number (ie. H has 1 electron)
SUBATOMIC PARTICLES: (think parts of atoms) Protons(p): positively charged ions located in the nucleus. Number of protons=atomic number Neutrons(n): neutral particles located in the nucleus; no charge. Use the formula Atomic Mass - Atomic Number= # neutrons
Subatomic Particles Continued: Electrons exist in space surrounding the nucleus in invisible shells (energy levels) electrons are transferred or shared between atoms to form chemical bonds Carry a negative ion charge Each energy shell has electrons. First shell always has 2 electrons Than 8 electrons on each other shell. MUST REMEMBER: Atomic Number=# of protons = # of electrons in every atom
Symbol Atomic Mass Atomic Number Charge (if ion)
EXAMPLE: How many protons, neutrons and electrons are found in an atom of Cs How do you get the number of protons? Protons=Atomic # How do you get the number of Electrons Electrons=Atomic # Mass number = sum of protons and neutrons Neutrons= Mass # (133) - atomic # (55) = 78 There are 78 neutrons Therefore, the Atomic number = protons and electrons There are 55 protons and 55 electrons in Cesium. Atomic Number
H Calculate how many protons, neutrons and electrons the element Hydrogen has. 1 1 Protons: 1 Neutrons: 0 Electrons: 1
Na Protons: 11 Neutrons: 12 Electrons: 11 Calculate how many protons, neutrons and electrons the element Sodium has.
Cl Protons: 17 Neutrons: 19 Electrons: 17 Calculate how many protons, neutrons and electrons the element Sodium has.
Al Protons: 13 Neutrons: 14 Electrons: 13 Calculate how many protons, neutrons and electrons the element Sodium has.
Re Protons: 75 Neutrons: 111 Electrons: 75 Calculate how many protons, neutrons and electrons the element Rhenium has.
REVIEW: From your knowledge of subatomic particles, fill in the chart below Element Name Atomic #Atomic Mass # Protons# Neutrons# Electrons Aluminum
Focus Questions: How does the mass of protons compare with the mass of electrons? What reason could there be for the number of protons being equal to the number of electrons in an electrically neutral atom? Is a particle an atom if it has no protons?