Mendeleev and the development of the Periodic table

Over time as elements have been discovered scientists have tried to observe patterns in their properties and behaviours, looking to list and categorise them accordingly. 

Döbereiner spotted patterns in sets of 3 elements, he called them triads. Newland arranged elements in order of atomic mass, he found that every 8th element had similar properties (although this did not work exclusively for all elements).  It was Dmitri Mendeleev who really got to grips with categorising elements into a table.  His ideas eventually led to the modern Periodic Table that we have now.   The video below explains the development of the Periodic Table:

So Mendeleev arranged his table in the following way:

• elements were arranged in rows of increasing atomic mass and columns of elements with similar properties,
• gaps were left for yet undiscovered elements, Mendeleev even predicted the atomic masses and properties of these elements. (Once discovered, it was found that he was very accurate with his predictions),
• where elements were in the wrong place when sorted by atomic mass, he swapped then so that they would be grouped by their properties e.g. tellurium and iodine were swapped so that iodine would be grouped with fluorine, chlorine and bromine,
• some elements were paired in the same space.

Mendeleev's table did not include a transition metal block or the Noble gases. As more was discovered about the atom and new elements found the Mendeleev's table evolved into the modern table that we now know.  In recognition of his role the 101st element was named after him - Mendelevium!

Reducing Our Impact on Global Warming - Carbon Capture and Storage

Evidence for the impact of carbon dioxide on global warming

There is much debate about the causes of global warming, some argue that it is just part of the Earths' natural cycle and that there have been periods of extreme heat and ice ages throughout the millennia. Whilst others say that increasing carbon dioxide in our time is contributing directly to global warming.  There are plenty of websites on the internet giving argue for and against these theories.  The Houston Chronicle blog typifies this showing that data can be used to argue for and against the impact of carbon dioxide. Click here.

The graph below (from http://www.discoveringantarctica.org.uk/alevel_2_3.html) shows a link between carbon dioxide levels and temperature over the last 600,000 years.  This data has been gathered by looking at ice core samples from Antarctica.  Click on the graph for more information.

It suggests that there is a link between carbon dioxide and temperature levels.  The greater the carbon dioxide the greater the temperature.  It also suggests that these temperature changes are cyclic.  At present the levels of carbon dioxide in our atmosphere are greater than at any time during the period of the graph above, it is also thought in some areas that the rise in global temperature is probably greater than would be expected in these normal temperature cycles.

The Artic Climate Impact Assessment (website click here) has shown that since the onset of the Industrial Revolution (1800s onwards) where the use of fossil fuels has increased, carbon dioxide emissions have increased rapidly as has global temperature.

Carbon-dioxide levels in the air closely track temperature records for the past 10 centuries. If they continue to parallel each other, global warming will only get worse. From: http://whyfiles.org/211warm_arctic/ Courtesy Arctic Climate Impact Assessment

How can carbon dioxide emissions be reduced?

Scientists believe that reducing carbon dioxide emissions could help reduce levels of global warming.  One method of doing this is by carbon capture and storage, the video below explains how this is being undertaken in Australia by the Australian Coal Association:

To summarise:

• carbon dioxide can be captured at the point of production,
• condensed into liquid form,
• then stored deep under sea beds in geological formation such as old oil fields, or underground in geological rock formations such as old coal seams.

For more information visit the Carbon Capture & Storage Association website. Click here.

Global Warming

What is Global Warming?

Carbon dioxide is one of a number of gases in our atmosphere that are known as 'greenhouse gases'.  The sun’s rays (made up of UV and Infra-red (IR) rays) pass through the atmosphere and warm the surface of the Earth.  These rays are reflected out into space again. Greenhouse gases such as carbon dioxide absorb some IR rays from the sun, and reflect them back towards the Earth, warming up the atmosphere and the Earth's surface.  These gases are needed as without them the surface temperature would be approximately 33^oC colder than it is now making it highly unlikely that plant and animal life would survive.

The Carbon Cycle

 

The carbon cycle is a naturally occurring process where carbon dioxide is removed from the atmosphere by organisms (such as plants) undergoing photosynthesis:

 

 

carbon dioxide  +    water     ---------->    glucose            +   oxygen

6CO₂(g)       +    6H₂O(l)   ---------->    C₆H₁₂O₆(s)         +   6O₂(g)

The carbon is trapped in the plant as glucose, this carbon can be transferred to animals when plants are eaten.

 Both plants and animals use glucose as a source of energy in the process of respiration:

glucose        +     oxygen  ---------->    carbon dioxide      +   water

C₆H₁₂O₆(s)    +     6O₂(g)    ---------->    6CO₂(g)                  +   6H₂O(l)

This (along with decomposition of plants and animals when they die) releases carbon dioxide back into the atmosphere.  This is not a problem as the amount carbon dioxide released is the same as the amount taken in when the plants grew originally, so the process can be considered ‘carbon neutral’.

 

On this basis carbon dioxide levels in the atmosphere would be sufficient to maintain a temperate climate.

Why is Global Warming an issue?

The problem exists in the combustion (burning) of fossil fuels.  Fossil Fuels contain carbon that was trapped millions of years ago.  This releases extra carbon dioxide into the atmosphere, which is not part of the natural carbon cycle.

 

This carbon dioxide absorbs more IR rays from the sun reflecting them back towards the Earth's surface, increasing the surface temperature.  This process is known as global warming, the video below describes the process:

 

 

Issues with Global Warming

As the surface temperature of the Earth increases a number of problems occur, many of which are linked together:

• Polar ice caps melt more quickly – sea levels rise, causing flooding in low lying coastal areas. Destroying habitats in both of these regions.

• Climate changes – Temperature rises will cause increased rainfall in some areas, tropical storms and flooding, yet in other areas would cause drought.

Shape memory alloys

Shape memory alloys are made of a mixture of metals, with the specific design that should they be deformed e.g. bent out of shape, they will retake their original shape (at least on macroscopic scale).  A common example of this are shape memory glasses.  In the video below you will see that the glasses easily return to their original shape, When frozen in liquid nitrogen the deformed shape exists until it warms back up to room temperature.

Over time repeated deforming of these alloys will cause them to stop returning to their original shape. Engineering scientists at University of Maryland in the US have developed a new alloys that have the ability to reform their original shape even after being bent 10 million times!  Click on the picture below to read the BBC News article.



Medic Mentor - Helping future prospective medics!

There are a few spaces remaining for Medic Mentor's MASTERCLASS.  

 

This course has been specifically designed to help students with their medical school applications by developing important skills essential to the application process. 

This is a very unique course, because there is a strong focus on developing knowledge and skills.  Students will receive continuous personalised support with their medical applications including personal statement help and interview preparation help.

This course is suitable only for year 10-13 students (this includes current year 9 students).

This will be taking place on 18th September at Cardiff University from 10:00-17:15.

 

 

Topics covered include:

 

• A history of Medicine and Surgery including important landmark events and recent developments
• An overview of the pillars of medical ethics
• Communication and presentation skills
• Basic teaching skills for students
• Personal statement 'Toolkit' and common pitfalls
• Updates on grade boundaries, competition ratios and entrance exams
• Essential Study and organisational skills
• CV padding tips
• Clinical history taking (how to talk to patients) and how to make the most of work experience placements
• Personal Professional Development packs 

 

MASTERCLASS Students receive personal mentoring following the course which includes:

• Detailed feedback on personal statements
• Personal Mentor follow up appointments
• MASTERCLASS school visits to useful courses in order to develop a greater insight into Medicine
• Exclusive access to an interactive Facebook group, so students can contact Mentors and ask questions directly
• Notes and factsheets to add to their PPD packs throughout the year
• Help and advice arranging work experience
• Exclusive publishing opportunities.

 

Registration is £100 and there are only a few spaces remaining.  This includes tea & coffee, refreshments and dinner.  Students will be given a PPD pack, exclusive access to online teaching material and certificates of attendance.  This is a highly interactive course and students receive personal feedback on their team working, leadership, teaching and presentation skills.  Prizes will also be awarded to students demonstrating exceptional skills during the course.

 

For more information please visit www.medicmentor.org  for further details about the course, the timetable and to book a place.

 

 

Chemistry in action at The University of Warwick

Year 10 pupils, an exciting opportunity has been made available by Warwick University for you to take part in a 4 day (3 nights) residential course looking at problems of modern society and how Chemistry can be used to develop solutions.

 

You will have the opportunity to:

 

• Learn about new and exciting chemical principles.
• Carry out investigations and experiments using state of the art research equipment.
• Work as a team to improve problem solving and communication skills.

 

Click on the images below for more details.



 

 

 

Scan the QR code on the second picture or click here to link to the website.

Hydrogen as a fuel - Blue plaque for Swansea scientist Sir William Grove

With oil reserves being depleted, there is a real need to find an alternative fuel source to power vehicles.  Could hydrogen be that source?

Hydrogen when burnt in oxygen produces a highly exothermic reaction, producing water as its only product:

hydrogen  + oxygen  ------->  water

H2(g)  + O2(g) -------> H2O(g)

We can see the dangers of hydrogen with the impact of the Hindenburg disaster:

The idea of using hydrogen in a fuel cell, whilst being discussed in the news now (January 2015) with Toyota making their patents freely available to companies to help develop technologies, is not a new one. The idea was first developed by Swansea scientist Sir William Grove in 1842!  He is now being recognised with a blue plaque, click on the picture for the BBC News article:

Hydrogen is an abundant element with it forming part of water, it is also a major constituent of fossil fuels.  It just needs to be separated to make it useful.  The following clip discusses how hydrogen could be obtained and why it might be useful, you might have to sign into YouTube to watch it:



The theories of Sir William Grove have been developed over the last century and in 2014 Toyota announced at CES (Consumer Electronics Show - global consumer electronics and consumer technology tradeshow) their developments in hydrogen fuel cell technology:

In the space of a year Toyota have developed their first hydrogen fuelled concept car:

Some exciting times ahead in the use of fuel cells for many applications!  Check out the new Toyota Mirai here.

Since originally posting in this 2015 (it is now 2020) the development of hydrogen as a fuel seems to have stalled and gone out of the media spotlight with electric cars and hybrids taking centre stage.  It appears that Toyota are still pushing on with hydrogen fuel cell technology, but the infrastructure is limited.  The pictures below illustrate how limited it is, with the green marks active fuel stations and the red as stations in development.