Bonding, Structure And Properties Of Matter Flashcards
What are the melting and Boiling Points of a Substance
-Melting point is the temperature at which a substance melts or freezes. Below this point, a substance is a solid.
-Boling point is the temperature at which a substance boils or condenses. Above this point, a substance is a gas.
-Between these points, a substance is a liquid.
-The more energy needed to break the bonds in a substance, the higher the melting/ boiling point.
Describe the Properties of Solids
-Cannot be compressed (no spaces between the particles).
-Cannot flow and take shape of container (particles cannot move).
-The particles are in neat rows, very close together and cannot move. The bonds are very strong.
Describe the Properties of Liquids
-Cannot be compressed (very few spaces between particles).
-Can flow and take shape of container (the particles can move).
-The particles are touching but able to move and are mixed up. The bonds are not very strong.
Describe the Properties of Gases
-Can be compressed (there are large spaces between the particles).
-Can flow and take shape of container (the particles can move).
-The particles are spread out and move very fast. There are no bonds.
Give Limitations of the Particle Model
-It assumes that particles are solid spheres but we know they are mostly empty space.
-It assumes that particles are stationary but we know particles vibrate and move around
-It assumes that there are no forces between particles but we know there are different types and strengths of attractions between particles.
Explain in Terms of Electrons, Why Elements React
-Elements react to achieve a full outer electron shell.
-Elements in group 0 (noble gases) do not react because they already have a full outer electron shell.
What are Ions
-An ion is an atom or molecule that has lost or gained an electron(s) to form a stable electronic structure.
-A positive ion is formed when a metal loses an electron from its outer shell.
-A negative ion is formed when a non-metal gains an electron.
What is Ionic Bonding
-An ionic bond is a strong electromagnetic attraction between oppositely charged ions.
-Ionic bonding is between metal and non-metal atoms.
-Metals lose an electron(s).
-Non-metals gain an electron(s).
What Happens during Ionic Bonding (Between Group 1 and Group 7)
-When a group 1 and a group 7 element react, ionic bonding takes place.
-The group 1 element loses one electron to form an ion with a charge of +1.
-The group 7 element gains one electron to form an ion with a charge of -1.
-Both ions have a full outer electron shell just like noble gases.
What Happens during Ionic Bonding (Between Group 2 and Group 6)
-When a group 2 and a group 6 element react, ionic bonding takes place.
-The group 2 element loses two electrons to form an ion with a charge of +2.
-The group 6 element gains two electrons to form an ion with a charge of -2.
-Both ions have a full outer electron shell just like noble gases.
Why are atoms uncharged before they react
-Before it reacts, an atom has the same number of protons and electrons.
-The negative electrons cancel out the positive protons, making the atoms uncharged.
Why does the Charge of Lithium and Fluorine change when they React
-When it reacts, the lithium atom loses one electron from its outer electron shell. Now it has two electrons (two negative charges) but it still has three protons (three positive charges).
-The two electrons can cancel out the charges on two of the protons. Therefore the lithium ion has one overall positive charge.
-When it reacts, the fluorine atom gains one electron into its outer energy level. Now it has ten electrons (ten negative charges) but it still has nine protons (nine positive charges).
-The nine protons can cancel out the charges on nine of the electrons. Therefore the fluorine ion has one overall negative charge
How does a Group 2 Element React with a Group 7 Element
-Each group 2 atom will lose 2 electrons from the outer energy level.
-However, each group 7 atom can only gain 1 electron (as they already have 7 electrons in their outer energy level).
-So one group 2 atom gives 1 electron each to two group 7 atoms.
What are the Advantages and Disadvantages of the Ball and Stick Model when Drawing Lattices
Advantage: The electrostatic forces of attraction (ionic bonds) are shown
Disadvantage: The sizes of each ion are not shown correctly
What are the Advantages and Disadvantages of the Space Filling Model Model when Drawing Lattices
Advantage: The sizes of each ion are shown correctly
Disadvantage: Electrostatic forces of attraction (ionic bonds) are shown
Describe what Happens to Particles when an Ionic Solid is Heated
-When we heat an ionic solid, the ions vibrate.
-As the strength of the vibration increases, there comes a point where the ions are moving with so much energy that the electrostatic forces between the ions weaken or break.
-Now the ions are free to move and the ionic compound has melted.
Explain why Ionic Compounds have High Melting and Boiling Points
-Ionic compounds have high melting and boiling points because the electrostatic attraction between positive, metal ions and negative, non-metal ions is strong.
-This takes a lot a lot of energy to weaken (melting point) or overcome (boiling point).
Explain why Ionic Compounds do not Conduct Electricity when Solid
-When solid, ionic compounds do not conduct electricity because the ions are fixed in a lattice by the strong electrostatic forces of attraction..
-This means they are not free to move and carry charge.
Explain why Ionic Compounds Conduct Electricity when Melted or Dissolved in Water
-Melting an ionic compound or dissolving it in water breaks the electrostatic forces of attraction between the ions.
-This means the ions are free to move and can carry charge.
Explain why Ionic Compounds are Brittle.
-Brittle means the compound shatters when hit.
-Ionic compounds are brittle because the layers in a lattice cannot slide over each other without repelling.
What is Covalent Bonding
-When a non-metal reacts with a non-metal, covalent bonding takes place.
-A pair of outer shell electrons is shared between two atoms.
-During covalent bonding, the atoms get a full outer shell, so become stable.
-Covalent bonding can be shown as a dot and cross diagram or a stick diagram.
Explain why only the Outer Electron Shell is shown when Drawing Covalent Bonds
Only the outer electron shells are involved in covalent bonding so we only show these on diagrams.
-Internal electron shells are already full so we don’t need to show these
Explain why one Atom of Oxygen must form Covalent Bonds with two Atoms of Hydrogen
-An oxygen atom has 6 electrons in its outer energy level.
-That means that 2 more electrons are required for oxygen to have a full outer energy level.
-Each hydrogen atom has 1 electron, so one oxygen atom has to form covalent bonds with two atoms of hydrogen.
Explain why one Atom of Nitrogen must form Covalent Bonds with three Atoms of Hydrogen
-A nitrogen atom has 5 electrons in its outer energy level.
-That means that 3 more electrons are required for nitrogen to have a full outer energy level.
-Each hydrogen atom has 1 electron, so one nitrogen atom has to form covalent bonds with three atoms of hydrogen.
Explain why one Atom of Carbon must form Covalent Bonds with four Atoms of Hydrogen
-A carbon atom has 4 electrons in its outer energy level.
-That means that 4 more electrons are required for carbon to have a full outer energy level.
-Each hydrogen atom has 1 electron, so one carbon atom has to form covalent bonds with four atoms of hydrogen.
Explain how Oxygen Atoms get Full Outer Electron Shells when they bond to form a Molecule
-Oxygen atoms have 6 electrons in their outer electron shell which means that 2 more electrons are required for a full outer energy level.
-In the case of the double covalent bond, each oxygen
atom puts 2 electrons into the bond.
-So both atoms now have 8 electrons in their outer electron shell (a full outer electron shell).
Explain how Nitrogen Atoms get Full Outer Electron Shells when they bond to form a Molecule
-Nitrogen atoms have 5 electrons in their outer electron shell which means that 3 more electrons are required for a full outer energy level.
-In the case of the triple covalent bond, each nitrogen
atom puts 3 electrons into the bond.
-So both atoms now have 8 electrons in their outer electron shell (a full outer electron shell).
What is a Small Molecule
-Small molecules are substances made up of non-metal atoms.
-A molecule is a particle made from atoms joined together by covalent bonds (between atoms).
Explain why Small Molecules have Low Melting/ Boiling Points
-Small molecules have low melting/ boiling points.
-This is because of weak intermolecular forces of attraction between the molecules requiring little energy to break them.
-The strong covalent bonds are not affected.
-Small molecules are often gases at room temperature.
What happens to the Melting/ Boiling Point as the Size of Covalent Molecules Increases.
-As the size of covalent molecules increases, the melting/ boiling points increase as well.
-this is because the strength of the intermolecular forces of attraction increases.
Explain why Small Molecules do not Conduct Electricity
-Small molecules do not conduct electricity because molecules are not electrically charged.
-They are neutral.
Explain why Large Covalent Structures are Strong
-Large covalent structures are strong (hard except graphite) because the atoms are held together by many strong covalent bonds.
-These take a lot of energy to break.