Atoms

• atoms- ✓the basic building blocks of matter that make up everyday objects.

  ✓ smallest particle of an element that has all the properties of that element

  ✓ made of subatomic particles: protons, neutrons, & electrons
• a molecule can have several- atoms
• Proton- positive charge/ +1
• electron- negative/ -1
• neutron- 0/ zero charge
• neutron+ proton= nucleus
• mass number- protons+neutrons
• neutral atom- atoms that have no net electric charge, meaning the number of protons is equal to the number of electrons.
• atomic number- will always have the same number of proton
• isotopes- Atoms with the same number of protons but different numbers of neutrons
• 2 main parts of Atom: 1. Nucleus

  ✓ 99.9% of the atom’s mass

  ✓ made of protons and neutrons

  2. Electron cloud or energy rings
• Which of the following particles is positively charged in an atom?- protons
• Which of the following determines the identity of a chemical element?- The number of protons
• What is the number of protons in an element with atomic number 17 and mass number 37?- 17
• Isotopes of a neutral atom have- the same number of electrons
• Elements having the same atomic number but different mass numbers are called- isotopes
• Deuterium is an isotope of a hydrogen atom. It contains- one proton and one neutron
• Which of the following contribute mainly to the mass of an atom?- neutron and proton
• The number of electrons in a neutral atom represents its- atomic number.
• Which of the following statements is correct regarding sodium atoms? Z(atomic number) = 11, A(atomic mass) =23 - It has 11 protons, 11 electrons, and 12 neutrons.
• Consider the species 72Zn, 75As and 74Ge. These species have: the same number of neutrons.
• What is the atomic weight of a hypothetical element consisting of two isotopes, one with mass = 64.23 amu (26.0%), and one with mass = 65.32 amu? = 65.0 amu
• Naturally occurring rubidium consists of just two isotopes. One of the isotopes consists of atoms having a mass of 84.912 amu; the other of 86.901 amu. What is the percent natural abundance of the heavier isotope? - 28%