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Chemistry / Re: How does chlorine become chloride when it bonds?

« on: 19/03/2018 21:20:14 »

everybody knows chlorine as poisonous.  Why would we have chlorine in one of the most over-used foods...

What makes Chlorine so dangerous is that it is eager to grab 1 extra electron to fill up its outer shell of electrons.
- It will do this to the surface of your lungs, skin and eyes, which is what makes it so lethal
- But after grabbing this electron, it becomes much more benign - somewhat like Argon just to its right, which also has this many electrons
- The same is true for the other elements in that right-hand column of the periodic table

What makes Sodium so dangerous is that it  it is eager to give away 1 electron to empty its outer shell of electrons.
- It will do this to the surface of your skin and eyes, which is what makes it so dangerous (fortunately, it has more difficulty getting into our lungs than chlorine)
- But after donating this electron, it becomes much more benign - somewhat like it's neighbor Neon, which also has this many electrons (you read the periodic table across and down, just like English, so Neon is just before Sodium)
- The same is true for the other elements in that left-most column of the periodic table

Sodium+Chlorine→Sodium Chloride is bliss on the kitchen table:
- Chlorine desperately wants to grab an extra electron
- Sodium desperately wants to give away an electron
- They do an electron swap; this is called an ionic bond, and tends to happen between elements on opposite sides of the periodic table
- it makes a fairly safe salt which we sprinkle on our boiled eggs in the morning
- Warning: Do not react Chlorine+Sodium at home! They are both very dangerous, and their romance is explosive...

The fact that elements above and below in the periodic table have similar (but not identical) properties is one thing that makes the periodic table so very useful.

There are other ways of joining atoms together - the organic molecules in our bodies frequently make use of covalent bonds, which occurs between elements which are "closer together" on the periodic table*
See: https://en.wikipedia.org/wiki/Chemical_bond

*those actinides & lanthanides look like they push elements far apart, when they shouldn't....

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Chemistry / Re: Chlorine / Chloride

« on: 19/03/2018 18:41:31 »

Sometimes elements acquire a Latin version of their name when they form compounds as well. For example, the Latin name for gold is "aurum". When gold bonds with cesium, it forms the ionic compound known as cesium auride. Gold is the more electronegative element of the two, so it gains the "-ide" suffix.

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Chemistry / Re: Chlorine / Chloride

« on: 19/03/2018 17:52:20 »

@vivian maxine - can you please follow the forum policy and format your thread titles are questions in future?

Also, can you please alter the title of this thread accordingly. (Action menu drop-down and click "modify" to do this).

Thanks

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Chemistry / Re: Chlorine / Chloride

« on: 19/03/2018 17:51:07 »

It's fairly obvious in most cases.

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Chemistry / Re: Chlorine / Chloride

« on: 19/03/2018 17:21:28 »

Oxygen: oxide
Hydrogen: hydride
Nitrogen  nitride
sulphur : sulphide

It's very common for the non-metal to change its name like this.

If you have a compound of two non metals, like phosphorous (V) oxide, it's helpful to know where the electrons are.
Since it's not "oxygen phosphide", we know that the electrons are on the oxygen.

There are probably exceptions- chemistry is good at that.

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Physics, Astronomy & Cosmology / Re: When we fly do we gain or lose weight?

« on: 27/09/2016 16:53:10 »

You need to distinguish between mass (an inherent quantity of an object) and weight (the force of gravity on an object).

In the absence of gravity, or in any gravitational field, the mass of a stationary object or an object moving at constant speed is unchanged but its weight depends on the strength of the gravitational field.

In the case of a moving object, at very high speeds the effective mass increases according to the relativistic equation that you can find on the internet (I can't type equations in a legible form here!) 

The relativistic mass gain by an airplane flying at any reasonable speed is negligible compared with the ablation of its surface by air friction.     

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Physiology & Medicine / Re: Can a living system export entropy?

« on: 22/09/2016 11:52:07 »

Cellular configurations define lower entropy, compared to the building blocks from which they came. For example, there is more entropy in amino acids moving in water, than there is in polymerized amino acids, perfectly folded into protein. The cells many configurations define lowered entropy compared to their monomers.

The second law states that the entropy of the universe has to increase. This is a net total. A cell will offset the low entropy defined by its many structures, by increasing internal entropy in other ways. One very important source of entropy is metabolism, where large food materials are broken down and burned to produce energy. In the presence of oxygen we end up with CO2 and H2O, with the water absorbed.

The cell will export entropy, by transporting the CO2, as bicarbonate, out of the cell. The loss of the CO2 offset, causes the cell to lower entropy once again, thereby requiring more offset for its structures, resulting in more metabolism.