An atom is often referred to as the building block of matter. Atoms have a nucleus surrounded by an electron cloud



Yüklə 457 b.
tarix22.05.2018
ölçüsü457 b.



An atom is often referred to as the building block of matter. Atoms have a nucleus surrounded by an electron cloud

  • An atom is often referred to as the building block of matter. Atoms have a nucleus surrounded by an electron cloud

  • Atoms are composed of smaller subatomic particles in an atom. The proton, neutron, and electron.

  • Each element is composed of one type of atom and can not be broken down into a simpler substance



Nucleus - Small, dense, positively charged center of the atom which contains most of the atom’s mass

    • Nucleus - Small, dense, positively charged center of the atom which contains most of the atom’s mass
    • The nucleus contains subatomic particles that have certain characteristics:
      • Protons (p+) - positively charged particles in the nucleus of the atom, contribute to the atom’s mass
      • Neutrons (no)- particles in the nucleus that have no charge, but contribute to the atom’s mass NEUTRAL


Electron cloud - an area encircling the nucleus where electrons are likely to be found

    • Electron cloud - an area encircling the nucleus where electrons are likely to be found
    • The cloud contains energy levels
      • electrons (e-)are negatively charged particles located in specific energy levels
      • energy levels completely surround the nucleus
      • there is a specific order for the electrons to fill the energy levels


Energy levels completely surround the nucleus

    • Energy levels completely surround the nucleus


valence electrons are in the outermost energy level and are the electrons involved in bonding

      • valence electrons are in the outermost energy level and are the electrons involved in bonding


The number of protons in the nucleus is the atomic number of that atom.

  • The number of protons in the nucleus is the atomic number of that atom.

  • The number of protons (+) equals the number of electrons (-) in a neutral atom

  • The mass number is the mass of the protons plus the mass of the neutrons

    • mass is reported in the SI units atomic mass units (amu)
    • Protons and neutrons each are given an amu of 1
    • Electrons have a mass of nearly zero






The mass number of an atom is for a particular isotope of that element

  • The mass number of an atom is for a particular isotope of that element

  • Mass number is the total number of protons and neutrons in the nucleus

  • Example for C-12:

    • 6 protons + 6 neutrons= 12
    • 12 is the mass number for Carbon-12
    • *13 is the mass number for Carbon-13 and comes from C-13 having 6 protons and 7 neutrons




Dostları ilə paylaş:


Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©genderi.org 2019
rəhbərliyinə müraciət

    Ana səhifə