Atoms and Ions C1

• What are all things made up of, including living and non-living entities?

  Atoms
• How many atoms are estimated to be in a single cell?

  More than 100 trillion
• What is the basic structure of an atom?

  A central nucleus surrounded by electrons in shells
• What are the two types of particles that make up the nucleus of an atom?

  Protons and neutrons
• What is the relative mass of protons and neutrons?

  One
• How does the mass of electrons compare to protons and neutrons?

  Electrons are about 2,000 times smaller
• What charge do protons have?

  Positive charge (+1)
• What is the charge of neutrons?

  No charge (neutral)
• What charge do electrons have?

  Negative charge (-1)
• How can you remember the charges of protons, neutrons, and electrons?

  Protons are positive, neutrons are neutral, and electrons are negative
• What is the typical radius of an atom?

  About 0.1 nanometers
• What is mostly found in an atom?

  Empty space
• How does the size of the nucleus compare to the size of the atom?

  The nucleus is 10,000 times smaller than the atom
• How many protons and electrons does the drawn atom have?

  Three protons and three electrons
• What happens when an atom gains or loses electrons?

  It becomes an ion
• What is a negative ion?

  An atom with more electrons than protons
• How do you denote a one minus negative ion?

  By having one extra electron
• What is a positive ion?

  An atom with more protons than electrons
• How do you denote a one plus positive ion?

  By having one less electron
• What information does the periodic table provide about elements?

  • Elemental symbol (e.g., O for oxygen, Li for lithium)
  • Atomic number (number of protons)
  • Mass number (total number of protons and neutrons)
• What does the atomic number indicate?

  How many protons an atom has
• How do you calculate the number of neutrons in an atom?

  Mass number minus atomic number
• How many neutrons does oxygen have if its mass number is 16 and atomic number is 8?

  8 neutrons
• How many neutrons does lithium have if its mass number is 7 and atomic number is 3?

  4 neutrons
• How many electrons does an atom have if the number of protons is equal to the atomic number?

  It has the same number of electrons as protons
• How many electrons does oxygen have if its atomic number is 8?

  8 electrons
• How many electrons does lithium have if its atomic number is 3?

  3 electrons