Категории: Все - reactivity - conductivity - electronegativity - stability

по Mila Alam 4 лет назад

453

Periodic Table Trends

The text discusses trends in the periodic table, focusing on the reactivity of different element groups with water and other substances. Alkali metals, when reacting with water, release enough heat to ignite, forming various oxides.

Periodic Table Trends

Periodic Table Trends

By: MILA ALAM

Discussion questions

1. Since sodium and potassium are high in reactivity, if one of them were to be extracted then its most likely that they decrease its reactivity. 2. Magnesium is more reactive than aluminum. My reason is that the lower the electronegativity is in an element, the more easily an atom loses an electron 3. Group 17 is more reactive than 16 and 18. The reason why first off is that group 18 is just filled with gases that have low electronegativities and also that it has a full valence shell. 16 on the other hand has 6 valence electrons which means they are unstable and are more reactive.

Trends in Chemical Properties

In some cases when elements from some groups, Alkali, for example, react poorly with it because enough heat is given off and that reaction ignites the water. Its reaction with oxygen forms monoxides, superoxides and etc. For Alkaline, it produces hydroxides and when reacted with water it forms metal hydroxide salts. Group 13 isn't very much reactive with water. Group 14 mostly did not react with water other than tin. In group 15, the element did not react with water, some dissolved but did not react. Group 16 the nonmetal oxides react with the water to form oxoacids. For group 17, they did react due to their different electronegativities. Finally, group 18 did not react either.

Trends in Physical Properties

While going through the periodic table, I noticed that the atomic radius increases when they move down a group and then left across a period. As for the melting points, I moved throughout the table, I noticed that group 1 had a low melting point. Then from the 2nd group, it started to increase as you move down but started to decrease again.

Metalloids

Some examples of Metalloids are Silicon, Boron and Arsenic. These elements have properties of both metals and nonmetals. Their physical properties are: shiny or dull, can be ductile or malleable and can be used as semiconductors. Its chemical properties are: having properties of metal and non-metals, mostly bonding like nonmetals and they have 3-6 valence electrons.

Non-metals

Some examples of non-metals are Carbon, oxygen and nitrogen. As physical properties for this group are dull in appearance, they are poor conductors and they are not ductile or malleable. For chemical properties, they 1 or have 3-6 valence electrons and they usually gain electrons when bonding.

Metals

Metals stay solid at room temperature other than Mercury. Some examples of metals can be Silicon, Arsenic and Boron. Physical properties can be shiny, it is ductile and malleable. It is a good conductor of heat and electricity. Also has high melting points.

Halogens

This group has elements that are highly reactive to Alkali and Alkaline earth metals. It also has 7 valence electrons, unlike the other 3 groups that have been mentioned. A physical property that relates to its reactivity is that the reactivity is a gas that forms negative ions (has one negative charge). Another physical property that only Iodine has, which is that it’s a solid having metallic appearance. Each type of gas has its own variety of colours which is easy to identify too. Now bringing back how it is highly reactive, it's due to them being unstable which means that if they had one more electron then they'd have a stable electron configuration. Halogens are poor thermal and electrical conductors.

Noble Gases

This group is nonreactive, it wasn't discovered after a period of time. All of the noble gases conduct electricity, they are colourless and odourless. Interestingly about this group is that each element has its own chemical properties but still ties in together. Going back to the fact they are not reactive, the explanation is that they have a complete valence shell. Meaning they have little tendency to gain or lose electrons. They are usually used for chemical reactions but as said before they have different chemical properties. The outer shell of their valence electrons is full which gives them a bit of a tendency to participate in chemical reactions.

Transition Metals

These metals are like iron, nickel and such. As physical properties they are fairly unreactive, they are also good conductors for heat/electricity and have high melting points. For chemical properties, Transition metals are able to bend and hammered into sheets. Transition metals have the ability to form complex ions. Lastly iron, an element from this group, reacts with water and oxygen at room temperature to form rust.

Alkaline Earth Metals

Alkaline earth metals are reactive (not as much as Alkali metals). They have 2 valence electrons which Alkali metals do not. For physical properties, we can look at Barium which is one of the elements. It is highly metallic, has higher melting points than Alkali metals and it is a good conductor for heat/electricity. Now going back to the 2 electrons for the chemical property, unlike Alkali metals, Alkaline loses 2 electrons when bonding to form cations. Alkaline metals are also extremely reactive with acid, for example, Beryllium is one of them. The elements can also improve other things like Magnesium, for example, can strengthen aluminum and can be a fire starter.

Alkali Metals

Alkali metals are known to be extremely reactive. One of the elements that are highly reactive is cesium. Just like most of the elements in this group, it’s physical properties are shiny, soft and have low melting points. For the chemical properties. As mentioned before, Alkali metals are highly reactive and it's because they only have one electron in their outer shell. So they are more likely to lose that electron in ionic bonding. Francium, especially, is highly reactive since it's also radioactive. Another chemical property that is seen in this element and the others is that when the elements react with water it form hydroxide. Alkali metals also can bond with Halogens (group 17) to form salts. Sodium, an element from the group, is something that we use in our lives. The form we use is sodium chloride, or as known, table salt and borax (cleaning supply) could be another example.