Presentation on theme: "The Atom How big is an Atom? n The average size atom (Al) is about 0.00000003 cm. n It would take a stack of 50,000 aluminum atoms to equal the thickness."— Presentation transcript:
How big is an Atom? n The average size atom (Al) is about cm. n It would take a stack of 50,000 aluminum atoms to equal the thickness of a sheet of aluminum foil. n Thats Small!!!!
Whats Inside an Atom? n An atom is made up of a team of three players: protons, neutrons, and electrons n They each have a charge, mass, and a location
Protons... n Charge: positive n Mass: 1 amu (atomic mass unit) n Location: Nucleus
Neutrons... n Charge: n Charge: none n Mass: n Mass: 1 amu (atomic mass unit) n Location: n Location: Nucleus
Electrons... n Charge: n Charge: negative n Mass: n Mass: almost zero n Location: n Location: electron clouds
Electrons vs Protons n The electrons negative charge is the same size as a protons positive charge. n They cancel each other out: n = 0 n Atoms like to have 0 charge.
Questions... n What particles are in the nucleus? n Explain why atoms are neutral. n Why do scientists say that most of the mass of an atom is located in the nucleus?
How Do Atoms of Different Elements Differ? n Lets compare a Hydrogen atom and a Helium atom…
Hydrogen... n Draw one proton. n Draw a circle around the proton. n Place one electron on the circle. n You have just created a hydrogen atom! n Hydrogen has no neutrons.
Helium n Draw n Draw two protons and two neutrons all together. an electron orbit around them. n Place n Place two electrons on the orbit. n You n You have just created a helium atom!!!
What is different? n The two different elements have different numbers of electrons, protons, and neutrons. n OK...
Are all atoms of an element the same? n Draw another Hydrogen atom, but this time add a neutron. n It is still Hydrogen because it has only one proton, but it has more mass in the nucleus. n It is called an isotope.
What is an Isotope? n Isotope - atoms that have the same number of protons but have different numbers of neutrons. n Some isotopes are radioactive. n Otherwise they are mostly the same as the regular atom.
How can you tell one isotope from another? n By their mass numbers. n mass number = protons + neutrons. n Different isotopes will have different mass numbers because they have different numbers of neutrons.
Lets see... n Hydrogen-1 has 1 proton and 0 neutrons. n Mass Number = 1 n Hydrogen-2 has 1 proton and 1 neutron. n Mass Number = 2
Questions… n List the charge, location, and mass of each particle. n Determine the number of protons, electrons, and neutrons in aluminum-27.