1. hydrogen
   tin
2. helium

He is helium. Because helium's density is so different from normal air, if you inhale it and then speak, it makes your voice sound hilarious.

1. lead
   lutetium
2. barium

Pb is lead, which is actually a pretty blue-white color just after it's been cut. It's only after exposure to air that lead turns into its familiar dull gray color.

1. sodium
   indium
2. scandium

Na is sodium, and it's a necessary element that appears in many familiar items such as sodium chloride -- table salt. It's also extremely reactive. If you throw a chunk of sodium into a lake, you'll see violent explosions, and yes, there are YouTube videos that serve as life lessons in this matter.

1. potassium
   sodium
2. krypton

K is the abbreviation for potassium. It reacts explosively when exposed to water, so you must handle it with extreme caution.

1. polonium
   radium
2. uranium

U is uranium, which in spite of its ominous reputation, is only a little radioactive compared to some other elements. It's much denser than lead and often used in nuclear weapons and nuclear power plants.

1. cobalt
   calcium
2. cerium

Co is cobalt, and once it is smelted, it has a silvery gray appearance. It's often used in the production of strong alloys, particularly those that require corrosion resistance.

1. sulfur
   selenium
2. tennessine

Se is selenium, a metal ore that rarely appears in any real amounts in nature. It can be used in industrial applications and in place of lead to create a non-toxic version of brass.

1. gallium
   platinum
2. phosphorus

P is phosphorous. Some types of phosphorous are essential for life. Others, like white phosphorous, are easily ignitable and can cause serious harm.

1. rhenium
   radon
2. radium

Rn is radon. It's a noble gas that's gained infamy for its prevalence in homes. It is odorless and tasteless, but constant exposure can cause lung cancer.

1. gold
   europium
2. ruthenium

Au is gold. Gold's atomic number is 79, and it's one of the most prized elements on Earth. About half of the gold that's mined is used for jewelry, and 10 percent is used in various manufacturing industries.

1. selenium
   fermium
2. tungsten

W is tungsten, which is also known as wolfram. It was first isolated in a lab in 1783 and it is used in many alloys. It's also very hard, and as such, it's good for things like weapons projectiles.

1. xenon
   vanadium
2. mercury

V is vanadium, which is a silvery metal that was first discovered in 1801. It's often used in steel alloys for surgical tools, crankshafts and other metal items.

1. dubnium
   erbium
2. hassium

Db is dubnium, and no, it's not named after former president George W. Bush. It's a highly radioactive transition metal, and it can only be produced by humans in a lab.

1. oganesson
   phosphorus
2. protactinium

Pa is protactinium, a dense metal that was discovered in 1913. It's extremely toxic and dangerously radioactive, so it can only be handled safely in a shielded glove box.

1. molybdenum
   manganese
2. mendelevium

Mn is manganese, which is a critical element for various metal alloys, like stainless steel. Most manganese ore is mined in Africa.

1. boron
   indium
2. einsteinium

Es is einsteinium, and it wasn't discovered until 1952 in the remains of a hydrogen bomb test. It's a soft, silvery metal and some of its isotopes are extremely radioactive.

1. californium
   caesium
2. bromine

Cf is californium, which has the atomic number 98. It's an extremely radioactive chemical element that has a number of uses, such as firing up nuclear reactors at power plants. It was first created in 1950.

1. platinum
   plutonium
2. promethium

Pu is, of course, plutonium which was first produced in real quantities during World War II. It was used in the atomic bomb that was dropped on Nagasaki, Japan.

1. lithium
   lanthanum
2. lutetium

La is lanthanum, a metallic chemical element that's been used in many lighting products, from lantern mantles to photography studio lights. It was discovered in 1839 but not fully isolated until 1923.

1. fluorine
   fermium
2. francium

Fr is francium, which was discovered in France in 1939. It's so rare (and so unstable) that it doesn't really have any purposes outside of laboratory research.

1. thulium
   thorium
2. titanium

Tm is thulium, a silvery gray chemical element in the lanthanide series. It's one of the rarest metals on Earth, but it's useful for laser, X-rays and other high-tech applications.

1. livermorium
   lutetium
2. lawrencium

Lv is livermorium, a very radioactive element. Scientists have never observed it in nature, but they've created it in labs. The U.S. and Russia worked together to discover this element in 2004.

1. iridium
   astatine
2. fluorine

Ir is iridium, a silvery-white transition metal used in many electronics applications. Although fairly rare on Earth, this element is often found in meteorites that crash into our planet.

1. gallium
   germanium
2. curium

Ga is gallium, and at room temperature, it's a pretty silver-blue color. It's not a free element in nature, but it's created for its many uses in electronics.

1. bismuth
   bromine
2. barium

Br is bromine, and it gets its name from an old Greek word that means "stench," and we totally didn't make that up. It's a reddish-brown liquid that readily turns to gas, and yes, it really smells terrible.

1. nickel
   nitrogen
2. neptunium

N is nitrogen, a colorless gas that was first discovered in 1772. It's one of the most common (and useful) elements in the universe. It's found in everything from fertilizer to drugs to bulletproof clothing.

1. magnesium
   moscovium
2. Hammer

Mc is not M.C. Hammer, it is moscovium. It was first created by a team of American and Russian scientists in 2003, and it's an extremely unstable and reactive element.

1. silicon
   strontium
2. tin

Sn is tin, a silver-white metal that has many of the most stable isotopes on the entire periodic chart. It's used in a lot of metal alloys, including the common tin can.

1. rubidium
   radium
2. iodine

Rb is rubidum, a highly reactive type of alkali metal. It can spark fires when it's combined with water. It has a number of useful industrial applications, and it is also used to make fireworks explode into a mesmerizing purple color.

1. boron
   beryllium
2. barium

Be is beryllium, a whitish-gray alkaline earth metal. When used in metal alloys, it allows for great rigidity and light weight in many products, but industrial workers must wear protection to prevent them from inhaling the dust, which can cause serious illnesses.