2.1.1 Atoms structure&Isotopes

• What are atoms composed of?

  Atoms are composed of subatomic particles.
• What is the significance of the nucleus in an atom?

  The nucleus contains the heaviest subatomic particles and is where the mass of an atom is concentrated.
• What particles are found in the nucleus of an atom?

  The nucleus contains neutrons and protons.
• Why is the mass of an electron considered negligible?

  Because the mass of an electron is much smaller than that of protons and neutrons.
• What is the overall charge of a neutral atom?

  A neutral atom has no overall charge.
• How are ions formed?

  Ions are formed when atoms gain or lose electrons, causing them to become charged.
• What determines the element of an atom or ion?

  The atomic number determines which element an atom or ion is.
• How can the number of protons in an unknown element be calculated?

  The number of protons can be calculated using the mass number and the number of neutrons.
• If an atom of lithium has an atomic number of 3, how many protons does it have?

  It has 3 protons.
• How many protons does a magnesium ion (Mg$^{2+}$) have?


  It has 12 protons.
• How many protons does a carbon atom have?

  A carbon atom has 6 protons.
• How can the number of protons in an unknown atom with mass number 63 and 34 neutrons be determined?

  By using the formula: Number of protons = mass number - number of neutrons.
• What is the number of protons in an atom of element X with mass number 63 and 34 neutrons?

  Element X has 29 protons.
• What is the relationship between protons and electrons in a neutral atom?

  A neutral atom has the same number of protons and electrons.
• What is a cation?

  A cation is a positively charged ion that has lost electrons.
• What is an anion?

  An anion is a negatively charged ion that has gained electrons.
• How many electrons does a magnesium ion (Mg$^{2+}$) have?


  A magnesium ion has 10 electrons.
• How many electrons does a carbon atom have?

  A carbon atom has 6 electrons.
• How does the number of electrons in an ion differ from its atomic number?

  The number of electrons in an ion differs from its atomic number based on its charge.
• What is the atomic number of a carbon atom?

  6
• How many protons does a carbon atom have in its nucleus?

  6 protons
• How do you calculate the number of protons in an atom?

  Number of protons = mass number - number of neutrons
• If the mass number is 63 and the number of neutrons is 34, how many protons are there?

  29 protons
• What element is represented by 29 protons?

  Copper
• What does it mean for an atom to be neutral?

  It has the same number of protons and electrons
• What is a cation?

  A positively charged ion that has lost electrons
• What is an anion?

  A negatively charged ion that has gained electrons
• How do you determine the number of electrons in ions and atoms?

  • For Mg²⁺: Atomic number is 12, loses 2 electrons, so has 10 electrons.
  • For Carbon atom: Atomic number is 6, so has 6 electrons.
  • For element X (mass number 63, 34 neutrons): 29 protons, so has 29 electrons.
• What is the atomic number of magnesium?

  12
• How many electrons does a neutral magnesium atom have?

  12 electrons
• How many electrons does a Mg²⁺ ion have?

  10 electrons
• What is the mass number of a carbon atom?

  12
• How do you calculate the number of neutrons in an atom?

  Number of neutrons = mass number - number of protons
• How many neutrons does a carbon atom have?

  6 neutrons
• If the mass number of magnesium is 24 and the number of protons is 12, how many neutrons does it have?

  12 neutrons
• How many neutrons does a carbon atom have if its mass number is 12?

  6 neutrons
• How many neutrons does element X have if it has 29 protons and a mass number of 63?

  34 neutrons
• What are isotopes?

  • Atoms of the same element
  • Same number of protons and electrons
  • Different number of neutrons
• How is the symbol for an isotope represented?

  Chemical symbol followed by a dash and mass number
• What are examples of isotopes of carbon?

  Carbon-12 and carbon-14