Chem topic 1

• matter

  anything that occupies space and has mass
• chemistry

  study of composition of structures and properties of matter
• mass


  defines the quantity of matter
• element

  substance made of only one atom on the periodic table
• atom

  smallest unit of an element that can exist stabily
• molecule

  contains more than one atom of the same type held together by a bond
• compound

  contains more than one atom of different types held together by a bond
• mixture

  material made of 2 or more different substances mixed but not bonded together
• pure substance

  constant composition
• heterogenous mixtures

  varying compositions from point to point
• homogenous mixtures

  uniform compositions
• subatomic particles

  make up an atom: protons, neutrons, electrons
• nucleus

  dense core of an atom
• orbitals

  paths
• valence shell

  outermost shell/orbital
• valence electrons

  electrons in the valence shell
• what electrons can participate in chemical bonding?

  valence electrons
• ions

  have an overal positive or negative charge
• ionization

  loss or gain of electrons
• cation

  positive charge
• anion

  negative charge
• lewis structure

  shows valence electrons around an element
• isotopes

  same element, different mass
• what can break down compounds?

  chemical changes
• what subatomic particles contribute to an elements mass?

  protons and neutrons
• what indicates the number of valence shells on the PT?

  row
• what indicates the number of valence electrons on the PT?

  column
• what does the element number indicate?

  number of protons and electrons
• why do elements ionize?

  to complete the octet rule
• what causes an ion to become a cation?

  looses electrons
• what causes an ion to become an anion?

  gains electrons
• which side of the PT is more likely to become a cation?

  left
• which side of the PT is more likely to become an anion?

  right
• what column is least likely to ionize due to following the octet rule?

  column 8
• why do elements want to follow the octet rule?

  octet is a stable formation
• how do isotopes change atomic weight?

  adding or loosing neutrons
• why are the atomic masses decimals on the PT?

  the mass is an average of all isotopes masses