6 Answers | Add Yours
The periodic table is arranged in rows and columns in which the elements have similar properties. When Mendeleev created the table in the late 1800s, he did so because he had noticed patterns in the elements that were known at the time; there were repeating characteristics, as elements increased in atomic weight. When he arranged the elements then known, he was able to leave gaps in appropriate places. Even though those elements had not yet been discovered, he knew that there had to be one that fit into that slot--and he was right. Some were discovered soon after.
As far as predictive powers, elements in the same row (period) decrease in atomic radius as you move from left to right. Elements to the right of the diagonal line dividing the table separate elements generally tending to be metals (on the left) from non-metals (to the right). You can also predict which elements will combine with others, and in what ratios, because the number of electrons in the shells can be deduced.
The alkali metals, found in group 1 of the periodic table, are highly reactive metals that do not occur freely in nature. These metals have only one electron in their outer shell. Therefore, they are ready to lose that one electron in ionic bonding with other elements. As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals.
The alkaline earth elements are metallic elements found in the second group of the periodic table. All alkaline earth elements have an oxidation number of +2, making them very reactive.
The Transition metals
The 38 elements in groups 3 through 12 of the periodic table are called "transition metals." As with all metals, the transition elements are both ductile and malleable, and conduct electricity and heat. Their valence electrons are present in more than one shell. This is why they often exhibit several common oxidation states.
The "other metals" elements are located in groups 13, 14, and 15. While these elements are ductile and malleable, they are not the same as the transition elements. These elements, unlike the transition elements, do not exhibit variable oxidation states, and their valence electrons are only present in their outer shell. All of these elements are solid, have a relatively high density, and are opaque. They have oxidation numbers of +3, ±4, and -3.
Metalloids are the elements found between the boundary that distinguishes metals from non-metals. Metalloids have properties of both metals and non-metals. Some of the metalloids, such as silicon and germanium, are semi-conductors.
Non-metals are the elements in groups 14-16 of the periodic table. Non-metals are not able to conduct electricity or heat very well. As opposed to metals, non-metallic elements are very brittle. The non-metals can be gases, such as oxygen and solids, such as carbon. The non-metals have no metallic luster, and do not reflect light. They have oxidation numbers of ±4, -3, and -2.
The halogens are five non-metallic elements found in group 17 of the periodic table. All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1.
The noble gases are found in group 18 of the periodic table. These elements have an oxidation number of 0. This prevents them from forming compounds readily. All noble gases have 8 electrons in their outer shell, making them stable.
The 30 rare earth elements are composed of the lanthanide and actinide series. One element of the lanthanide series and most of the elements in the actinide series are synthetic, that is, human-made. All of the rare earth metals are found in group 3 of the periodic table, and the 6th and 7th periods.
Yes, we can use the table to determine the physical and chemical properties of an element. The table is arranged in vertical rows and horizontal periods, and the elements are positioned based on their increasing atomic weight, their proton number. All the positions of the element were constructed by Mendeleev, the inventor of the periodic table in the late 1800s, and later on, other scientists add on to it. The non-metal are usually positioned at the right of the table while the rest are occupied by non-metal, and is seperated by a thick dark line. You can used the table to determined the electronic structure of elements, based on the atomic number. You can check the charges of the ion of the element present in the element. Also, if you go down a group, you would realise the atoms gets bigger (or atomic radius), and properties of elements become more metallic as elements start losing electrons more easily.
this is quite easy. you have keep in mind certain basic properties of elements from which certain properties can be explained. however exceptions are always there and for those exceptions also explanation is there.
certain basic properties:
1. atomic radis - increses down the group due to increase in shells and decrease across a period due to increase in nuclear charge on outermost shell
2. ionisation enthalpy inc. across due to dec. in size and dec. down the group due to increase in size.
3 electron gain enthalpy less negative down the group due to increase in size
also factors like hund's rule can be kept in mind for certain exceptions.
Mendeleev created the first periodic table based on atomic weight. He observed that many elements had similar properties, and that they occur periodically. Hence, the table’s name.
His periodic law states that the chemical and physical properties of the elements vary in a periodic way with their atomic weights. The modern one states that the properties vary with atomic number, not weight.
Elements in Mendeleev's table were arranged in rows called periods. The columns were called groups. Elements of each group had similar properties.
The Periodic table can be divided into nine families of elements each having similar properties. The families include:
The modern periodic table, based on atomic number and electron configuration, was created primarily by a Russian chemist, Dmitri Ivanovich Mendeleev, and a German physicist, Julius Lothar Meyer, both working independently. They both created similar periodic tables only a few months apart in 1869.
We’ve answered 301,510 questions. We can answer yours, too.Ask a question