L3 Periodic table Flashcards
How is the modern periodic table arranged?
= elements are arranged in order of atomic number, not atomic mass
- Periods = horizontal rows
- Groups = vertical columns - similar cemical propeties, steady chnage in chemical propertes as the atoms get bigger
How is the modern periodic table arranged?
= elements are arranged in order of atomic number, not atomic mass
- Periods = horizontal rows
- Groups = vertical columns - similar chemical properties, steady change in chemical properties as the atoms get bigger
What is the periodic law?
= properties of elements are periodic functions of their atomic numbers.
- When elements are arranged in order of increasing atomic no., there is a periodic pattern in their physical & chemical properties.
What are the alkali metals?
What properties do they have?
= Group 1, s block
e.g Li, Na, K
Properties:
- Silver coloured, soft (small no. of electrons - weak metallic bonds) metals
- Highly reactive
- Rarely found in pure elemental form in nature
- 1 valence e-
What are the alkaline earth metals?
What properties do they have?
= Group 2, s block e.g. Be, Mg, Ca Properties: - Silver coloured, soft (small no. of electrons - weak metallic bonds) metals - Highly reactive - 2 valence e-
What are Nobel gases?
What properties do they have?
= Group 8, p block
e.g. Argon, helium
Properties:
- Chemically inert (unreactive) BUT not biologically inert so they have medical applications e.g. anesthetic (xenon can react with neurotransmitters)
- Nonmetallic
- Gaseous under standard conditions
- Full outer e- shells = stable configuration
What are halogens?
What properties do they have?
= Group 7, p block
e.g. F, Cl, Br, I
Properties:
- Highly reactive - they even form bonds with themselves (diatomic)
- Highly toxic e.g Cl (g) = chemical weapon
- Gases, low-boiling (Br) or low-melting (I) materials
What are the metalliods?
What properties do they have?
= 6 elements, p block
= Boron, Silicon, Germanium, Arsenic, Antimony & Tellurium
Properties:
- Some metallic properties: they can conduct electricity e.g. Ar/Si can be used for modern communications
- Some non-metallic properties: covalency
What are the transition metals?
What properties do they have?
= d block
= “an element with at least one oxidation state that has a partially filled d-subshell”
e.g. Co, Cu, Fe
Properties:
- High densities, melting & boiling points
- Multiple oxidation states/valencies
- Can undergo both reduction & oxidation and use e- from two outer orbitals for combination with other elements
- Form coloured compounds and complex ions (in solution)
What are the lanthanides?
What properties do they have?
= rare earth metals, 15 elements with atomic no. 57-71, f block
e.g. Lanthanum La, Cerium Ce, Lutetium Lu
Properties:
- Partially filled f-subshells
- Shiny and silvery-white, and stain easily when exposed to air
- Have high melting and boiling points
- Some are unstable/radioactive
- Multiple structures possible (multiple crystaline forms with slightly different properties)
What are the actinides?
What properties do they have?
= 15 elements with atomic numbers 89-103, f block
e.g. Actinium Ac, Uranium U
Properties:
- Radioactive/unstable
- Very dense metals with distinctive structures
- Numerous allotropes may be formed (plutonium has at least 6 allotropes)
- Combine directly with most non-metals
What are non-metals?
What properties do they have?
= Groups 4-6 of the periodic table, p block
e.g. Carbon C, Nitrogen N, Oxygen O
Properties:
- Don’t conduct heat/electricity very well
- Very brittle -> cannot be rolled/pounded into sheets like metals
- Have no metallic luster/don’t reflect light
- Tend to form molecular compounds -> building blocks of biochemistry
*Halogens are also non-metals (they just have more complex chemical/physical properties)
How to properties change down a group?
There is a regular gradation of physical and chemical properties moving from top to bottom of the group.
How does the size of atoms change going down a group?
Atom size increases down the group - size of nucleus/e- clouds increases
How does metallic character change going down a group?
Metallic character increases going down
- Apparent in groups IVA, VA, and VIA, begins with non-metals (C, N, O) and ends with metals (Pb, Bi and Po)
