Atoms & Ions

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

  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 particles 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 charge do neutrons have?

  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
• What happens to an atom when it 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
• What does the periodic table represent?

  Different types of atoms called elements
• What does the elemental symbol represent?

  The one or two letter symbol for an element
• What does the atomic number indicate?

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

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

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

  4 neutrons
• How many electrons does an atom have if it has 8 protons?

  8 electrons
• How many electrons does an atom have if it has 3 protons?

  3 electrons
• What are the key components of an atom's structure?

  • Central nucleus
  • Protons (positive charge)
  • Neutrons (neutral charge)
  • Electrons (negative charge)
  • Electrons orbit in shells around the nucleus
• What are the characteristics of protons, neutrons, and electrons?

  • Protons:
  • Charge: +1
  • Relative mass: 1
  • Neutrons:
  • Charge: 0
  • Relative mass: 1
  • Electrons:
  • Charge: -1
  • Relative mass: very small (often considered 0)
• What is the relationship between atomic number and the number of protons, neutrons, and electrons?

  • Atomic number = number of protons
  • Number of neutrons = mass number - atomic number
  • Number of electrons = number of protons (in a neutral atom)