Chemistry, 17.07.2019 17:40 ednalovegod

1. how are atomic radii and ionization energy related (i. e. as atomic radius increases, what happens to the ionization energy)? 2. generally, as you go from left to right across a period on the periodic table, what happens to atomic radius? what about ie? 3. generally, as you go down a group in the periodic table, what happens to atomic radius and ie? 4. why does radius increase as you go down a group (hint: think of b-r diagrams)? why would an increase in radius make it easier to lose an outer electron (i. e. give a lower ionization energy)?

Answers: 1

Show answers

Answers

1) Atomic radii and ionization energy related in this way: when we move from left to right across the periodic table, the atomic radii of elements becomes smaller. Having a smaller radius, the electrons are placed very tightly to the nucleus than larger atoms. So, the ionization energy that is required to withdraw an electron would be greater in regard to the smaller atoms.

2) As you go from left to right across a period on the periodic table the atomic the radius tend to decrease.Keep in mind that atomic radius always decreases from left to right within a period. It happens because the number of protons and electrons across a period are increased.

3) Generally, as you go down a group in the periodic table, the atomic radius increases. Remember that when you move down a group in the periodic table, the number of filled electrons increases.

4) The radius increases as you go down a group because of electron shielding. And, the main cause is that number of protons and electrons across a period. Take into account that atomic radius increases from top to bottom within a group.

5) An increase in radius will make it easier to lose an outer electron because it is placed farther from the nucleus. To be more precise, the increased distance becomes weaker the force of attraction. Then there usually occurs the effect called 'screening', during which the electrons from inner electron shells block some of the charge.

Answer from: Quest

but know think of it in terms of bond breaking and bond making.

h–h + h–h + o=o ==> h–o–h + h–o–h

as you can see from the diagram, theoretically, more energy is released by forming water, than was absorbed in breaking up the original hydrogen and oxygen molecules.

the energy level of the fuel + oxygen is higher than that of water.

therefore the fuel + oxygen mixture has the potential to release potential chemical energy as heat energy or, crucially, electrical energy, if the reaction can be made to go via oxidation and reduction reactions involving electron transfer.

see this page for more details of the full bond energy calculations

a fuel cell is a device to make electricity that functions like an electrical cell or battery that you supply with a fuel (liquid or gas) and an oxidant (oxidising agent, usually oxygen gas) which react together in a redox reaction (oxidation + reduction) to release energy as a flow of electrons i.e. an electrical current capable of doing useful work.

the oxidation of the fuel and the reduction of the oxidant reactions take place on electrodes (see diagram on right, all fully explained further down the page).

fuel cells essentially a device to release the chemical potential energy of combustible fuels as electrical energy at a much lower temperature and without the flame!

so, the idea of a hydrogen–oxygen fuel cell is to release the energy from hydrogen reacting with oxygen, not as heat as in normal combustion in air, but as useful electrical energy i.e. a practical electricity supply.

hydrogen-oxygen fuel cells are much efficient than conventional power stations or batteries (e.g. zinc-carbon) because the electrical energy is directly generated from the chemical reaction between the oxidant and the fuel - there are no complications with boilers, turbines and generators.

in fossil fuel power stations, motor vehicles, coal/gas fires etc. quite a percentage of energy is lost as waste heat.

with a fuel cell there are fewer stages in producing the useful energy, so there is less opportunity to lose potentially useful energy e.g. waste heat, friction from moving parts etc.

a hydrogen–oxygen fuel cell is a non–polluting clean fuel since the only combustion product is water.

fuel cells do not produce pollutants like carbon monoxide, sulfur dioxide and nitrogen oxides - gases you get from fossil fuel combustion in power stations or burnt road vehicles..

cars powered by fuel cells would be quite an environmental advantage in cities, where electric cars are already beginning to be significantly used in developed countries.

fuel cells could replace larger batteries which are not easily recycled and contain highly toxic metal compounds.

it would be an ideal fuel on this basis e.g. for motor vehicles, but that's not the only factor to consider!

it would be ideal if the hydrogen fuel could be manufactured by electrolysis of water e.g. using solar cells.

hydrogen can be used to power fuel cells.

it all sounds wonderful but, still technological problems to solve for large scale manufacture and distribution of 'clean' hydrogen gas or use in generating electricity and its rather an inflammable explosive gas!

explanation:

fuel cells e.g. the hydrogen-oxygen fuel electrical cell

fuel cells have to be supplied by an external source of fuel (e.g. hydrogen) and an oxidant e.g. oxygen or air.

the hydrogen or any other fuel is oxidised electrochemically inside the fuel cell to produce a potential difference i.e. a voltage capable of producing a working current.

the overall chemical reaction in a hydrogen fuel electrochemical cell involves the oxidation of hydrogen by oxygen to produce only water.

hydrogen fuel cells offer an alternative to rechargeable cells and batteries.

a fuel cell will produce a potential difference ('voltage') and a workable electric current until one of the reactants is used up.

hydrogen gas can be used as fuel.

it burns with a pale blue flame in air reacting with oxygen to be oxidised to form water.

hydrogen + oxygen ==> water

2h2(g) + o2(g) ==> 2h2o(l)

Answer from: Quest

How do we find the answer?

Another question on Chemistry

Chemistry, 22.06.2019 01:30

Follow the steps provided in the simulation to add water to the graduated cylinder, select one of the three samples (copper, silver, or gold), set its mass to the values given in the statements below, and calculate its density. here is a summary of the steps required: add water by clicking and holding prepare a known volume of water button. until the desired volume of water has been added. if more than the desired volume is added, click the reset button. button and redo the procedure. a single click will add about 21.0 ml of water. to set the mass, click and hold weigh out metal button. until the desired amount of metal is added to the weighing pan. once the desired mass of the metal is added, release the button. transfer the metal to water and then click on calculate density button. to see how the density is calculated using water displacement to measure the volume of the solid. to save time you can approximate the initial volume of water to â±1 ml and the initial mass of the solid to â±1 g. for example, if you are asked to add 23 ml of water, add between 22 ml and 24 ml. which metals in each of the following sets will have equal density? check all that apply.

Answers: 1

Answer

Chemistry, 22.06.2019 20:30

Is a chemical message sent by another individual.

Answers: 1

Answer

Chemistry, 22.06.2019 20:30

We are hoping to create 5.72 grams of glucose. the plant was given 4.75 liters of co2 and 2.81 g of h20. which reactant was the limiting reagent? how much excess mass did we have of the other reactant?

Answers: 3

Answer

Chemistry, 23.06.2019 01:00

Atoms contain subatomic particles called protons and neutrons. when these protons and neutrons spilt, a lot of energy is released

Answers: 3

Answer

You know the right answer?

1. how are atomic radii and ionization energy related (i. e. as atomic radius increases, what happen...

Questions