The Clear Science Staff was just reading Energy-critical elements for sustainable development in the current issue of the MRS Bulletin. Energy-critical elements or ECEs are those thought to be important for emerging energy technologies. Notice the elements chosen: the rare earths (pink), the platinum group metals (blue), metalloids used for solar panels (green), and lithium for batteries.

The Clear Science Staff was just reading Energy-critical elements for sustainable development in the current issue of the MRS Bulletin. Energy-critical elements or ECEs are those thought to be important for emerging energy technologies. Notice the elements chosen: the rare earths (pink), the platinum group metals (blue), metalloids used for solar panels (green), and lithium for batteries.

We mentioned the precious metals, which are a loose association of elements that are metallic, non-radioactive, useful, expensive, and rare. They generally occupy an area of the transition metals on the periodic table. Location in the periodic table has to do with the numbers of protons and electrons that make up an atom, and elements near each other have similar physical and chemical properties.
Silver and gold fall in the same group (column) as copper, which is Group 11 in the new system (and Group IB in the system most of the Clear Science staff grew up with). Sometimes these are called the coinage metals.
Ruthenium, rhodium, palladium, osmium, iridium, and platinum are collectively called the platinum group. This corresponds to Groups 8, 9 and 10 (or VIIIB).
Occasionally you hear some of these metals called "noble metals" because they are unreactive and resistant to most chemicals. Aqua regia ("royal water") was so named because it can dissolve platinum and gold, which is a difficult task indeed. 

We mentioned the precious metals, which are a loose association of elements that are metallic, non-radioactive, useful, expensive, and rare. They generally occupy an area of the transition metals on the periodic table. Location in the periodic table has to do with the numbers of protons and electrons that make up an atom, and elements near each other have similar physical and chemical properties.

Silver and gold fall in the same group (column) as copper, which is Group 11 in the new system (and Group IB in the system most of the Clear Science staff grew up with). Sometimes these are called the coinage metals.

Ruthenium, rhodium, palladium, osmium, iridium, and platinum are collectively called the platinum group. This corresponds to Groups 8, 9 and 10 (or VIIIB).

Occasionally you hear some of these metals called "noble metals" because they are unreactive and resistant to most chemicals. Aqua regia ("royal water") was so named because it can dissolve platinum and gold, which is a difficult task indeed. 

We talked about how in the universe the most abundant elements by far are hydrogen and helium. (We’re thinking about what Carl Sagan means by “We’re made of star stuff.”)
Consider this: we all know what the periodic table looks like. However, in the moments right after the Big Bang, the periodic table looked much different. In fact it looked very simple. Easy to memorize! (Can we all go back and have chemistry class one minute after the Big Bang please?)
PS at the very instant of the Big Bang, there were no elements.

We talked about how in the universe the most abundant elements by far are hydrogen and helium. (We’re thinking about what Carl Sagan means by “We’re made of star stuff.”)

Consider this: we all know what the periodic table looks like. However, in the moments right after the Big Bang, the periodic table looked much different. In fact it looked very simple. Easy to memorize! (Can we all go back and have chemistry class one minute after the Big Bang please?)

PS at the very instant of the Big Bang, there were no elements.

Pick an element, like iron (Fe, #26), and let’s see where its electrons are. 
You read the table left to right, just like text. So it starts with hydrogen (H, #1) and goes from there. An atom has equal protons and electrons, so iron, which gets its identity from its 26 protons, also has 26 electrons.

As we read down to iron, we go through these parts of the table: s, another s, p, s, p, s, and d. We use arrows, UP and DOWN, to indicate the electrons in the orbitals. It looks a bit like Hangman.

There is one rule: the orbitals that belong together (like that last section of p orbitals) fill up one at a time before the electrons double up. So it has a few orbitals that only have an UP, with no corresponding DOWN.

Pick an element, like iron (Fe, #26), and let’s see where its electrons are. 

You read the table left to right, just like text. So it starts with hydrogen (H, #1) and goes from there. An atom has equal protons and electrons, so iron, which gets its identity from its 26 protons, also has 26 electrons.

As we read down to iron, we go through these parts of the table: s, another s, p, s, p, s, and d. We use arrows, UP and DOWN, to indicate the electrons in the orbitals. It looks a bit like Hangman.

There is one rule: the orbitals that belong together (like that last section of p orbitals) fill up one at a time before the electrons double up. So it has a few orbitals that only have an UP, with no corresponding DOWN.

 
Atomic orbitals are where electrons “orbit” the nucleus. They look kind of like kidneys, pears, and bells. (Rather than like the orbits of planets around the sun.)
The shape of the periodic table tells you what kind of orbital an electron goes in. This is why the table looks like it does.
Orbitals hold 2 electrons each. The p-block is 6 elements wide, and p orbitals come in 3’s. (It’s like: if a car holds 2 people then 6 people have to fit in 3 cars.)

Atomic orbitals are where electrons “orbit” the nucleus. They look kind of like kidneys, pears, and bells. (Rather than like the orbits of planets around the sun.)

The shape of the periodic table tells you what kind of orbital an electron goes in. This is why the table looks like it does.

Orbitals hold 2 electrons each. The p-block is 6 elements wide, and p orbitals come in 3’s. (It’s like: if a car holds 2 people then 6 people have to fit in 3 cars.)

To talk about magnetic moments, we are first going to talk about electrons. And for that, we’re back to the periodic table.
Awhile back, we talked about the f-block on the periodic table. We can go further: all parts of the table go in a block. These blocks have to do with electrons, and it’s electrons that lead to magnetism (and many other things).
We’ve left the ferromagnetic elements on the table above. Can you see a pattern about where they fall?

To talk about magnetic moments, we are first going to talk about electrons. And for that, we’re back to the periodic table.

Awhile back, we talked about the f-block on the periodic table. We can go further: all parts of the table go in a block. These blocks have to do with electrons, and it’s electrons that lead to magnetism (and many other things).

We’ve left the ferromagnetic elements on the table above. Can you see a pattern about where they fall?

Protons and electrons are equal in an atom’s natural state.
The atomic number tells how many protons an atom has. That determines its identity as one element or another. It will also have that many electrons in its orbitals, at least to start with.
The number of electrons does not determine an atom’s identity. Rather, this determines how elements will react and bond with each other.
Swapping and sharing electrons is how atoms interact. Water, which is not an element, is made up of hydrogen (Element 1) and oxygen (Element 8) sharing electrons. You probably already knew that.

Protons and electrons are equal in an atom’s natural state.

The atomic number tells how many protons an atom has. That determines its identity as one element or another. It will also have that many electrons in its orbitals, at least to start with.

The number of electrons does not determine an atom’s identity. Rather, this determines how elements will react and bond with each other.

Swapping and sharing electrons is how atoms interact. Water, which is not an element, is made up of hydrogen (Element 1) and oxygen (Element 8) sharing electrons. You probably already knew that.

What’s that disconnected block at the bottom of the periodic table?
The f-block is written down at the bottom connected by arrows just to make the table easier to read. You could shove it in where the arrows show it goes, making the rest of the table scoot over. But then the table gets so long and skinny it’s hard to read.

What’s that disconnected block at the bottom of the periodic table?

The f-block is written down at the bottom connected by arrows just to make the table easier to read. You could shove it in where the arrows show it goes, making the rest of the table scoot over. But then the table gets so long and skinny it’s hard to read.

But where does the name “Periodic Table” come from?
It’s “periodic” because elements have properties that recur in regular intervals as you add protons. The table is written so these elements fall in columns or groups.
There are several ways to name groups. For example with
names (“Alkali Metals” for example)
roman numerals and letters (“IA”)
a simple number (“Group 1”)
You may see all 3 of these at different times, but the concept is the same: The group belongs together.

But where does the name “Periodic Table” come from?

It’s “periodic” because elements have properties that recur in regular intervals as you add protons. The table is written so these elements fall in columns or groups.

There are several ways to name groups. For example with

  • names (“Alkali Metals” for example)
  • roman numerals and letters (“IA”)
  • a simple number (“Group 1”)

You may see all 3 of these at different times, but the concept is the same: The group belongs together.

Starting with Element 1, the periodic table adds one proton at a time. It counts up: Element 2 (two protons), Element 3 (three protons), etc.
When it gets all the way to the right, it returns to the left, just like written text.

Starting with Element 1, the periodic table adds one proton at a time. It counts up: Element 2 (two protons), Element 3 (three protons), etc.

When it gets all the way to the right, it returns to the left, just like written text.