bonds and molecules

• What is necessary to show what happens in a chemical reaction?

  Understanding chemical equations is necessary to show what happens in a chemical reaction.
• What is one way to show a chemical reaction?

  A word equation is one way to show a chemical reaction.
• What happens when methane burns in oxygen?

  Methane burns in oxygen to produce carbon dioxide and water.
• What are the reactants in the methane combustion reaction?

  The reactants are methane and oxygen.
• What are the products of the methane combustion reaction?

  The products are carbon dioxide and water.
• What does the arrow in a chemical equation represent?

  The arrow shows that the reactants react completely to form the products.
• What is a symbol equation?

  A symbol equation uses the chemical symbols of each molecule involved in the reaction.
• What is the chemical symbol for methane?

  The chemical symbol for methane is $CH_4$.
• What is the chemical symbol for oxygen?

  The chemical symbol for oxygen is $O_2$.
• Why do we write $O_2$ instead of $O$ in chemical equations?


  We write $O_2$ because oxygen exists as a molecule made up of two atoms.
• What is the first step in balancing a chemical equation?

  The first step is to ensure the same total number of each type of atom on either side of the arrow.
• How do you know if a chemical equation is balanced?

  A chemical equation is balanced if the number of each type of atom is the same on both sides of the equation.
• What is the rule regarding changing small numbers in balancing equations?

  You cannot change the small numbers because it would change the actual type of chemicals in the equation.
• How do you increase the number of oxygen atoms on the left side of the equation?

  You increase the number of oxygen atoms by putting a 2 in front of $O_2$.
• Why can't you use one and a half molecules of oxygen when balancing equations?

  You cannot use one and a half molecules because you must keep whole numbers when balancing equations.
• What is the main topic discussed in today's video?

  The arrangement of electrons in atoms
• How do you balance the number of hydrogens on the right side of the equation?

  You can balance the number of hydrogens by increasing the number of water molecules from one to two.
• Why is having a full outer shell of electrons important for atoms?

  It is necessary for atoms to be stable
• What is the result of balancing the methane combustion equation?

  The balanced equation shows the same number of each type of atom on both sides of the reaction.
• What happens to an atom with an incomplete outer shell?

  It will react with another atom to gain or lose electrons
• What is the atomic number of sodium?

  11
• What is the chemical reaction for sulfuric acid and sodium hydroxide?

  Sulfuric acid plus sodium hydroxide goes to form sodium sulfate plus water.
• How many protons and electrons does sodium have?

  11 protons and 11 electrons
• What is the recommended order for balancing elements in a chemical equation?

  It is recommended to balance the least common elements first.
• How are electrons arranged around the nucleus of an atom?

  In shells or energy levels
• How many hydrogens are on the left side of the sulfuric acid and sodium hydroxide reaction?

  There are three hydrogens on the left side of the reaction.
• How many electrons can the first shell hold?

  Two electrons
• How many sodium atoms are on the right side of the sulfuric acid and sodium hydroxide reaction?

  There are two sodium atoms on the right side of the reaction.
• How many electrons can the second shell hold?

  Up to eight electrons
• How do you balance sodium in the sulfuric acid and sodium hydroxide reaction?

  You balance sodium by putting a 2 in front of sodium hydroxide.
• What is the recommended order for placing electrons in the shell diagram?

  Place a single electron in the top, right, bottom, and left positions before pairing
• What is the common problem when balancing chemical equations?

  A common problem is needing to add more water molecules to balance the equation.
• What happens when there are still electrons left after filling the second shell?

  They are placed in the third shell
• What should you do after balancing a chemical equation?

  You should double-check to see if the equation is balanced.
• Why is sodium considered unstable?

  It has one electron in its outer shell instead of eight
• What is the final step after balancing a chemical equation?

  The final step is to ensure that the equation is exactly balanced.
• What do most atoms want to do to achieve stability?

  React to form molecules or compounds
• What are the noble gases known for regarding their electron configuration?

  They have completely full outer shells
• How would you determine the electron arrangement of argon?

  Find argon on the periodic table and note its atomic number, which is 18
• What is the electron structure of argon?

  Two electrons in the first shell, eight in the second, and eight in the third