In the spirit of the wonderful photobook The Elements by Theodore Gray (which I have previously blogged about), starting a collection of elements is a great way of introducing yourself (or your children) to basic chemistry. Here are some suggestions, and a list of 24 elements to start with….
2: Helium (He)
Helium is lighter than air, so balloons are often filled with helium.
6: Carbon (C)
Carbon is most easily added to your collection in the form of charcoal. Zinc–carbon batteries have a carbon rod at the centre.
7: Nitrogen (N)
Air is about 78% nitrogen. To add nitrogen to your collection, just fill a small bottle with air.
8: Oxygen (O)
Air is about 21% oxygen. To add oxygen to your collection, just fill a small bottle with air.
9: Fluorine (F)
Fluorine is a toxic gas. But octahedral fluorite crystals (calcium fluoride, CaF2) make a great addition to a collection.
11: Sodium (Na)
Sodium is a reactive metal which will spontaneously catch fire when in contact with water. But sodium chloride (ordinary table salt, NaCl) is perfectly safe.
12: Magnesium (Mg)
Magnesium is a flammable metal, but you can substitute crystals of Epsom salts (magnesium sulfate, MgSO4), which can be obtained from a pharmacy.
13: Aluminium (Al)
Aluminium (aluminum in the USA) is most easily available as aluminium foil.
14: Silicon (Si)
Silicon is widely used in transistors and integrated circuits (chips).
15: Phosphorus (P)
The side of a box of matches is largely composed of phosphorus.
16: Sulfur (S)
Sulfur powder, also called “flowers of sulfur,” is available from pharmacies.
17: Chlorine (Cl)
Chlorine is a toxic yellowish-green gas. But sodium chloride (ordinary table salt, NaCl) is perfectly safe.
20: Calcium (Ca)
Calcium is a reactive metal, but you can substitute crystals of calcite (calcium carbonate, CaCO3) or gypsum (calcium sulfate, CaSO4).
24: Chromium (Cr)
Chromium is used for plating (“chrome plating”) to prevent rusting. Also, “stainless steel” is between about 16% and 25% chromium.
26: Iron (Fe)
Iron is one of the most widely used metals. Iron nails are easy to add to your collection. Like nickel and cobalt, iron is attracted by a magnet.
28: Nickel (Ni)
The United States “nickel” coin is actually only 25% nickel (and 75% copper), but objects made of pure nickel can be found. Indeed, Canadian “nickel” coins from 1955–1981 are almost pure nickel.
29: Copper (Cu)
Copper pipes are widely used in plumbing. You can buy copper plumbing fittings, or get offcuts of pipe from a plumber. Copper electrical wire is also easy to find.
30: Zinc (Zn)
Galvanised iron is coated with zinc to prevent rusting. Also, filing off the copper coating on a US penny reveals a coin made mostly of zinc.
47: Silver (Ag)
A silver coin, or a piece of silver jewellery, would make a fine addition to your collection.
53: Iodine (I)
Iodine is a dark solid, but is sold in pharmacies as a brown solution in alcohol, called “tincture of iodine.”
60: Neodymium (Nd)
Neodymium is one of the “rare earth” elements. Neodymium magnets are the most common form of strong magnet. They are made of an alloy of neodymium, iron and boron (Nd2Fe14B).
74: Tungsten (W )
The filament in an incandescent light bulb is made from tungsten (but because of the danger of broken glass, only an adult should attempt to remove the filament, and then only with very great care).
79: Gold (Au)
A gold coin, or a piece of gold jewellery, would make a truly wonderful addition to your collection. Alternatively, for under $10, science museums will sell impressive-looking bottles of gold leaf floating in liquid.
82: Lead (Pb)
A fishing sinker is probably the easiest lead object to find.
So there you are. Those could be the first 24 elements in your collection!
Scientific Gems 
Tony
What an interesting idea! I would advise caution however when you add Polonium to your collection.
Seriously though, have you seen this excellent interactive version of the Periodic Table from the RSC?
http://www.rsc.org/periodic-table
Nigel
Some elements are definitely in the “don’t do this at home” category.
And yes, that’s nice!
Other, perhaps easier to obtain, examples of Tungsten are darts, many are now made using tungsten for a better size to weight ration, and the hardened tips of an old circular saw blade which are Tungsten Carbide. (please do not break the tips off of a good saw)
Darts are a good example.