Elements

• What is an element?

  A substance made up of atoms
• What defines an element in terms of atomic structure?

  All atoms have the same number of protons
• What is the significance of the number of protons in an atom?

  It determines the type of atom
• How can atoms differ from each other?

  By having different numbers of protons, neutrons, and electrons
• What is the term for a substance containing atoms with the same number of protons?

  Element
• How many different elements are there approximately?

  About 100
• What do all atoms of a particular element have in common?

  They have the same number of protons
• How do different elements relate to their atomic structure?

  Different elements have different numbers of protons
• What is the atomic number of hydrogen?

  1
• What is the atomic number of helium?

  2
• What is the difference between isotopes of the same element?

  They have different numbers of neutrons
• What are the two common isotopes of carbon?

  Carbon-12 and Carbon-13
• How does atomic mass differ from atomic number?

  Atomic mass considers protons and neutrons
• Why is atomic mass used instead of atomic number in some contexts?

  Because it reflects the total number of nucleons
• What are the key characteristics of isotopes?

  • Same number of protons
  • Different number of neutrons
  • Different atomic masses
• What are the differences between elements and compounds?

  • Elements consist of one type of atom
  • Compounds consist of two or more types of atoms
  • Elements cannot be broken down into simpler substances
• What is the periodic table?

  • A tabular arrangement of elements
  • Organized by increasing atomic number
  • Displays symbols and atomic masses
• How do atomic structure and chemical properties relate?

  • Atomic structure determines chemical behavior
  • Number of electrons influences reactivity
  • Elements in the same group have similar properties
• How many protons does Carbon-13 have?

  6 protons
• How many neutrons are in Carbon-13?

  7 neutrons
• Why is atomic mass used instead of mass number when referring to an element?

  Because many elements can exist as different isotopes
• What does average atomic mass account for?

  It accounts for different masses and abundances of isotopes
• How do you calculate the relative atomic mass of an element?

  • Use the formula:

  $A_r =$$\frac{\sum (isotope\ abundance \times isotope\ mass)}{\sum abundances\ of\ all\ isotopes}$
• What is the relative atomic mass of Copper-63?

  69.2%
• What is the relative atomic mass of Copper-65?

  30.8%
• How do you calculate the relative atomic mass of copper to one decimal place?

  Use the formula with given abundances
• What is the formula for calculating the relative atomic mass of copper?

  $A_r =$ \frac{(69.2 \times 63) + (30.8 \times 65)}{69.2 + 30.8}
• What is the final calculated relative atomic mass of copper?

  63.6
• What are the characteristics of atoms, elements, and isotopes?

  • Atoms consist of protons, neutrons, and electrons
  • Elements have the same number of protons and electrons
  • Isotopes have different numbers of neutrons
• Why is it important to know the differences between atoms, elements, and isotopes?

  To understand their properties and behaviors
• What is the significance of the number of protons and electrons in an atom?

  They determine the element's identity
• How do isotopes differ from each other?

  By having different numbers of neutrons
• What is the relationship between isotopes and the stability of an element?

  Some isotopes are stable while others are not
• What are the key differences between stable and unstable isotopes?

  • Stable isotopes do not undergo radioactive decay
  • Unstable isotopes decay over time, emitting radiation
• What is the atomic structure of Silicon-28?

  3 stable isotopes
• What is the abundance of Silicon-28?

  92.2%
• What is the abundance of Silicon-29?

  4.7%
• What is the abundance of Silicon-30?

  3.1%
• How do you calculate the relative atomic mass of silicon?

  Use the formula with given abundances
• What is the formula for calculating the relative atomic mass of silicon?

  $A_r =$ \frac{(92.2 \times 28) +$(4.7 \times 29) +$ (3.1 \times 30)}{92.2 + 4.7 + 3.1}