chem topic 1

• 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 much smaller is the mass of an electron compared to protons and neutrons?

  Two thousand 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 approximate 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 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 indicating it has 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 atomic number indicate?

  The number of protons in an atom
• 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 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
• 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 an atom made up of?

  An atom is made up of a central nucleus comprising protons and neutrons, with electrons orbiting around it.
• What determines which element an atom is?

  The number of protons in the nucleus determines which element an atom is.
• What is the smallest element?

  The smallest element is hydrogen.
• How many protons does a hydrogen atom have?

  A hydrogen atom has one proton in its nucleus.
• How many protons and neutrons does a helium atom have?

  A helium atom has two protons and two neutrons in its nucleus.
• How are elements organized in the periodic table?

  Elements are organized in the periodic table with each box representing a different element.
• What does the number in the bottom left of a nuclear symbol represent?

  The number in the bottom left of a nuclear symbol represents the atomic number, which is unique to that element.
• What does an atomic number of two indicate about an atom?

  An atomic number of two indicates that the atom is helium, as it has two protons.
• What is the atomic number of carbon?

  The atomic number of carbon is six.
• If an atom has three protons, what element is it?

  If an atom has three protons, it is lithium.
• What does the symbol 'C' represent?

  The symbol 'C' represents carbon.
• What does the symbol 'Li' stand for?

  The symbol 'Li' stands for lithium.
• What are isotopes?

  Isotopes are different forms of the same element that have the same number of protons but a different number of neutrons.