Chemistry BTEC Unit 1

• How many naturally occurring elements are there?

  92
• What defines an element?

  A substance made of one type of atom
• What is gold made of?

  Gold atoms
• What is the periodic table used for?

  To learn about elements and their properties
• What are the first 5 elements in the periodic table?

  • Hydrogen
  • Helium
  • Lithium
  • Beryllium
  • Boron
• How do elements combine to form compounds?

  Through chemical reactions, not mixtures
• What are the two types of compounds?

  • Covalent compounds
  • Ionic compounds
• What is an ion?

  An atom or molecule with a charge
• What happens when an atom gains or loses electrons?

  It becomes an ion
• What are examples of positive ions?

  Na⁺, Mg²⁺, Ca²⁺
• What are examples of negative ions?

  Cl-, F-
• What charge do metal ions typically have?

  Positive
• What charge do non-metal ions typically have?

  Negative
• What are some common polyatomic ions?

  • Nitrate [NO(3)]
  • Hydroxide (OH)
  • Carbonate [CO(3)]
  • Sulfate [SO(4)]
• What is the importance of balancing chemical equations?

  To have the same number of atoms on both sides
• What is the balanced equation for methane and oxygen?

  CH(4) + 2O(2) → CO(2) + 2H(2)O
• What are the steps to balance a chemical equation?

  1. Count atoms of each element
  2. Adjust coefficients to balance
  3. Ensure same number on both sides
  4. Repeat until balanced
• Who developed the periodic table?

  Dmitri Mendeleev
• What is a compound?

  A substance formed from two or more elements
• How do mixtures differ from compounds?

  Mixtures are not chemically combined
• What is the significance of balancing chemical equations?

  It ensures conservation of mass in reactions
• Where are electrons located in an atom?

  Electrons are in shells around the nucleus
• What are the principal quantum numbers for electron shells?

  n equals one, two, three, etc.
• What are the names of the subshells in electron configuration?

  S, P, D, and F subshells
• How many types of orbitals are in the S subshell?

  One orbital
• How many orbitals are in the P subshell?

  Three orbitals
• How many orbitals are in the D subshell?

  Five orbitals
• How many electrons can each orbital hold?

  Two electrons
• What is the maximum number of electrons in the first shell?

  Two electrons
• What is the maximum number of electrons in the second shell?

  Eight electrons
• What is the maximum number of electrons in the third shell?

  Eighteen electrons
• What is the electron configuration of fluorine with nine electrons?

  1s2 2s2 2p5
• How do electrons fill orbitals in an atom?

  They fill lower energy orbitals first
• What analogy is used to explain electron filling in orbitals?

  People choose free pairs of seats
• What is the electron configuration of calcium with 20 electrons?

  1s2 2s2 2p6 3s2 3p6 4s2
• What is the electron configuration of a magnesium ion (Mg2+)?

  1s2 2s2 2p6
• What does the electron configuration of magnesium ion resemble?

  It resembles neon's configuration
• What should you practice to master electron configurations?

  • Draw electron configuration diagrams for the first 20 elements
  • Draw diagrams for the ions of the first 20 elements
• How do you determine the charge of an ion for group elements?

  • Group 1: +1
  • Group 2: +2
  • Group 7: -1 or -2
  • Group 0: No ion formation
• What is the atomic number of calcium?

  20