Chem

• Who discovered the nucleus and protons?

  Rutherford
• Who discovered neutrons?

  Chadwick
• What does the current model of the atom include?

  Electrons on shells, protons and neutrons in the nucleus
• What is the mass and charge of protons?

  Mass of one and a charge of plus one
• What is the mass and charge of neutrons?

  Mass of one and a charge of zero
• What is the mass and charge of electrons?

  Mass of one two-thousandths and a charge of minus one
• What information does the periodic table provide about elements?

  The element's name, symbol, atomic number, and mass number
• What does the atomic number represent?

  The number of protons and electrons in an atom
• How is the mass number calculated?

  By adding the number of protons and neutrons
• How many protons does calcium have if its atomic number is 20?

  20 protons
• How many neutrons does calcium have if its mass number is 40?

  20 neutrons
• What defines an isotope?

  Atoms with the same number of protons but different numbers of neutrons
• How many neutrons does carbon-12 have?

  6 neutrons
• How many neutrons does carbon-14 have?

  8 neutrons
• Why does chlorine have a mass of 35.5?

  It reflects the relative abundance of its isotopes
• What is the significance of the periodic table?

  It lists all known elements and provides information about them
• How do you calculate the average mass of chlorine isotopes?

  By multiplying each isotope's mass by its abundance and dividing by 100
• What is a compound?

  Two or more elements that are chemically bonded together
• What was a flaw in Newlands' periodic table?

  He grouped elements with very different properties together
• What was Mendeleev's key contribution to the periodic table?

  He left gaps for undiscovered elements and predicted their properties
• Who created the first periodic table?

  Newlands
• What do groups in the periodic table indicate?

  The number of electrons in the outer shell
• What do periods in the periodic table indicate?

  The number of electron shells in an atom
• How many electrons does magnesium have if its atomic number is 12?

  12 electrons
• How many electrons are in magnesium's outer shell?

  2 electrons
• What is the maximum number of electrons the first shell can hold?

  2 electrons
• What is the maximum number of electrons the second shell can hold?

  8 electrons
• What happens to metals when they lose electrons?

  They become positively charged ions
• What happens to non-metals when they gain electrons?

  They become negatively charged ions
• What charge do elements in group one form when they lose an electron?

  Plus one ions
• What charge do elements in group two form when they lose two electrons?

  Plus two ions
• What charge do elements in group six form when they gain two electrons?

  Minus two ions
• What charge do elements in group seven form when they gain one electron?

  Minus one ions
• What is ionic bonding?

  The transfer of electrons from a metal to a non-metal
• How does magnesium oxide form through ionic bonding?

  Magnesium transfers its electrons to oxygen
• What is a dot and cross diagram used for?

  To represent the transfer of electrons in ionic bonding
• What is the atomic number of sodium?

  11
• What happens to sodium when it forms an ion?

  It loses one electron and becomes positively charged
• What is sodium chloride?

  An ionic compound formed from sodium and chlorine
• What is the structure of ionic compounds?

  A giant ionic lattice