Science - Chemistry

• Atoms

  the smallest part of a chemical element containing subatomic particals called protons, neutrons and electrons
• Protons (2 points)

  • positively charged
  • Determines the atomic number
• Electrons (2 points)

  • negatively charged
  • found in electron energy levels
• neutrons (2 points)

  • Neutral charge
  • found in the nucleus
• Atomic mass comes from

  The protons and neutrons in the nucleus of an atom
• the nucleus has an overall charge of what?

  Postive charge
• Elements on the periodic table are in order of

  Increasing atomic number
• Rows and column's in the PT are called what?

  • Rows are Periods
  • Columns are Groups
• Groups (3 Points)

  • Elements in groups have similar properties (reacting in a similar matter
  • Groups all have the same electron arrangement for their valence shell
• The three types of elements that can be found in the Periodic table are


  Metals, non-metals and metalloids
• Label The element

  Oxygen

  A) Atomic Number

  B) Chemical symbol

  C) element name

  D) Atomic mass

  
• The outer shell of an Atom is called the Valence shell. Electrons in the valence shell are called Valence electrons.
• The further you go down a group, the more reactive the elements become due to the valence electrons being further away from the positive nucleus so it takes less energy for them to be removed
• Metals 


  • located on the left side and middle section if the periodic table
  • conductor for heat and electricity
  • shiny
• A stable atom has a full Valence shell
• if an atom is not stable, it undergoes changes to achieve the same electron configuration as a Nobel Gas
• ion

  • formed when an atom loses or gains electrons, resulting in a cation or anion
• Atoms can share electrons to achieve a stable valence shell. they will have 7 electrons and share 1 electrons with another Atom of 7 electrons to both have stable atoms
• Chemical compound

  • 2 or more ions joined together through electrostatic attraction, resulting in a compound
  • the swap and drop technique is used to write chemical compounds

  
• cations

  • a ion with a positive charge
  • formed when an atom loses an electron (more protons then neutrons and a positive net charge)
• Anion

  • ion with a negative charge
  • formed when an atom gains a electron (more electrons than protons creating a overall negative net charge)
• Atoms determine whether a atom is going to gain or lose an electron is all about energy

  • Few electrons as possible
  • gaining or losing electrons require the same amount of energy
  • Atoms will choose the path that requires the least amount of energy
• We can predict an ion charge by looking at their group number. if its group 1 then we know that the elements will have to lose 1 electron to achieve a full valence shell, forming a +1 cation
• What groups form ions?

  • 1,2,3,13,15,16,17

  A) 2+

  B) 1+

  C) charges vary

  D) 3+

  E) 3-

  F) 2-

  G) 1-

  
• Atomic radius

  • The distance from the centre of the nucleus to the valence shell
• Metals have a regular arrangement of atoms within them
• Delocalised electrons

  • Electrons that are lost and move freely around the lattice of metal cations
• In metallic bonding, their is a high electrostatic attractive between the negatively charge delocalised electrons and the positive cations, holding them firmly together
• electrostatic attraction holds together the metal
• most metallic bond have a high melting and boiling point. Also good conductors of electricity and heat. and are solid in room temperature
• Delocalised electrons can carry electrical currents and thermal energy
• Physical properties of metals

  • Malleable - Metals can be easily bent or hammered into shapes
  • ductile - can be drawn into wires
  • Metallic bonds are non-directional
• When force is applied to to metal and the cations move, so do the delocalised electrons due to not being in a fixed structure
• some Atoms don't form ions as they either have a full valence shell (noble gases), or have 4 valence electrons so their is no need to gain/lose electrons as it would take the same amount of energy either way
• why are ions formed?

  because atoms want to have a full valence shell to become stable but if they dont have a full valence shell, they must lose or gain electrons to achieve a stable atom
• random ionic charges i need to know

  • silver forms a cation with +1 charge
  • Zinc forms a cation with +2 charge
  • aluminium and Gallium form cations with +3 charge
• Atomic number

  • determined by the number of protons in the nucleus
• determine location of protons, neutrons and electrons

  protons - nucleus

  neutrons - nucleus

  electrons - the energy levels
• the average mass of subatomic particles

  • It is the average of all the isotopes of an element
• how does the arrangement of electrons relate to groups on the periodic table

  • groups determine the amount of valence electrons in their group via their number (group 2: 2 valence electrons) and groups determine the reactivity of an element through their group