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Periodic Table
The Periodic Table is a tabular arrangement of the elements in increasing order oftheir atomic numbers, so that elements with similar properties are in the same column. There are 18 columns, called groups, and seven rows, which are called periods, in the modern periodic table. Questions about the Periodic Table: its history and creation, trends, groups/families, and periods are asked in our Periodic Table category.
11,356 Questions
In physics is a capital E the symbol for evaporation or energy?
In physics, a capital E typically represents energy. Evaporation is often represented by a lowercase e with a subscript, such as e_v.
There are no elements that start with a W, however, W is the symbol for Tungsten.
Why is the atomic number important to the atom?
The atomic number corresponds to the number of protons in an atom.
Hydrogen is the first element on the Periodic Table of Elements because it only has one proton.
The number of protons in an atom and the number of neutrons in an atom are what make atoms different.
What are 2 main divisions of the periodic table?
DEFINITION:The orderly arrangement of elements is called "PERIODIC CLASSIFICATION".
INTRODUCTION: When a very large number of elements become known to scientists , it was felt that they must be arranged in a systematic order because a systematic classification provides a clear idea and information about the properties of elements and make it easier to predict the properties of different elements. This classification provides the inter-relationship of scientific facts.
Early Attempts at Classification Of Element:In old days, element were arranged in the ascending order of their atomic masses.
1.Law of Triads/ DOBEREINER'S TRIADS:In 1829, a German scientist Dobereiner made use of the relationship between atomic masses and properties of elements.
Drawback:This rule is not for all the elements.
2.NEWLAND'S law of octave:In 1866, a British scientist, Newlands, reported his "law of octave" by arranging elements according to increasing order of their atomic masses. He noticed that "Every eight element, starting form any point, approximately has similar properties".
Newland's arrangement was applicable only to a few elements after that it was failed.
3.LUTHER MEYER'S CLASSIFICATION:In 1864, a German Chemist Luther Meyer published on incomplete periodic table .He included about 56 elements arranged in a group from I to VIII. He plotted the values of different physical properties and obtained different curves .In these graphs, he observed that element with similar physical properties occupy similar positions in the curve
For example :Alkali metals occupy the peak of the curves.
Halogen occur on the ascending portions of the curve.4.MENDELEEV'S PERIODIC TABLE:
In 1869, a Russian chemist, Mendeleev, on the basis of physical and chemical properties discovered a relation known as "PERIODIC LAW".According to the law:"The properties of element are the periodic function of their atomic masses".
Mendeleev arranged the known elements according to increasing order of their atomic masses because,according to him fundamental property of an element was atomic mass.He further divided and arranged these eight groups into subgroups.Mendeleev's periodic table was very precise and provided the basis of modern periodic classification.
Original statement of Mendeleev's periodic law:
1.The elements,if arranged according to their atomic weights show an evident periodicity of properties.
2.Elements which are similar with regards to their chemical properties have atomic weights which are either nearly the same value or which increase regularly.
3.The arrangement of the elements or of groups of elements in the order of their atomic weights,corresponds with their so called valencies.
4.The elements which are most widely distributed in nature have small atomic weights and sharply defined properties.They are therefore typical elements.
5.The magnitude of the atomic weight determines the character of an element.
6.The discovery of many as yet unknown elements may be expected.
7.The atomic weight of an element may sometimes be corrected by the aid of a knowledge of those of adjacent elements.
8.Certain characteristic properties of the elements can be foretold from their atomic weights.
MERITS OF MENDELEEV'S PERIODIC TABLE
Mendeleev's periodic table offered the following advantages in understanding the properties of elements.
1. There was a regular gradation in physical and chemical properties of elements.
2. The group number of an element indicates highest oxidation state that it can attain.
3. There were many vacant spaces in Mendeleev's periodic table for the elements to be discovered.He named them Eka-Boron, Eka-Aluminium and Eka-silicone He also predicted the properties of these undiscovered elements including atomic masses.These elements were discovered as Sc ,Ga and Ge with same features as he predicted.
4. Mendeleev's arrangement helped to correct atomic masses of a number of elements.
DEMERITS IN MENDELEEV'S PERIODIC TABLE
1. For placing the elements in proper groups,the order of the elements according to atomic mass was reversed in certain cases. He placed Iodine (127) after Tellurium (128) Potassium (39) and Ni (58)after Co (59).Which is against his periodic law but correct according to properties.
2. Mendeleev's periodic table does not provide a clear idea about the structure of atom.
3. Lanthanide and Actinide have been assigned places in the periodic table which is against the periodic law.
4. Alkali metal and coinage metals (Cu,Ag and Au) which differ widely in properties are placed into the same group.
5. There is no separate position for isotopes in his periodic table.
6. The change in atomic mass of two successive elements is not constant. Hence it is not possible to predict the number of missing elements by knowing the atomic masses of two known elements. DIC TABLE1. For placing the elements in proper groups, the order of the elements according to atomic mass was reversed in certain cases. He placed Iodine (127) after Tellurium (128) Potassium (39) and Ni (58) after Co (59). Which is against his periodic law but correct according to properties.
2. Mendeleev's periodic table does not provide a clear idea about the structure of atom.
3. have been assigned places in the periodic table which is against the periodic law.
4. Alkali metal and coinage metals (Cu, Ag and Au) which differ widely in properties are placed into the same group.
5. There is no separate position for isotopes in his periodic table.
6. The change in atomic mass of two successive elements is not constant. Hence it is not possible to predict the number of missing elements by knowing the atomic masses of two known elements.
DEMERITS IN MENDELEEV'S PERIODIC TABLE
1. For placing the elements in proper groups, the order of the elements according to atomic mass was reversed in certain cases. He placed Iodine (127) after Tellurium (128) Potassium (39) and Ni (58) after Co (59). Which is against his periodic law but correct according to properties.
2. Mendeleev's periodic table does not provide a clear idea about the structure of atom.
3.have been assigned places in the periodic table which is against the periodic law.
4. Alkali metal and coinage metals (Cu,Ag and Au) which differ widely in properties are placed into the same group.
5. There is no separate position for isotopes in his periodic table.
6. The change in atomic mass of two successive elements is not constant. Hence it is not possible to predict the number of missing elements by knowing the atomic masses of two known elements.
What elements have low electronegativity?
The elements with low electronegativity are the metals, specifically the alkali metals and alkali earth metals. The elements further to the left of the periodic table will have lower electronegativity than those farther to the right.
In Science what silver colored metallic element has the symbol HG?
The silver-colored metallic element with the symbol Hg is mercury. It is a heavy, toxic metal that is liquid at room temperature.
Is molar mass equal to the atomic number?
No, molar mass is the mass of one mole of a substance, expressed in grams per mole. Atomic number is the number of protons in the nucleus of an atom. Molar mass takes into account the mass of all the protons, neutrons, and electrons in a mole of a substance.
How does the bohnr model of the atom relate to the periodic table?
The Bohr model of the atom helped explain the arrangement of electrons in discrete energy levels or shells around the nucleus. This concept of electron shells provided a basis for understanding the organization of the elements on the periodic table, where elements are arranged by increasing atomic number and by recurring chemical properties based on their electron configurations.
What happens when HNO2 undergoes disproportionation?
When HNO2 undergoes disproportionation, it can transform into different products depending on the conditions. In acidic solution, it can form nitric oxide (NO) and nitrous acid (HNO3). In basic solution, it can produce salt of nitrite ion (NO2-) and salt of nitrate ion (NO3-).
What are the atomic number for the hydrogen isotope with 1 neutron?
Atomic number of hydrogen is (always) 1. The mass number is 2, sum of number of protons (1 in H) and neutrons (1 in H in this case). This isotope of hydrogen is called deuterium.
By the way: neurons (without t) is a very different thing!
In stars more massive than the Sun fusion continues until the core is almost all?
Iron. Iron is the heaviest element that can be produced through nuclear fusion in a star, and once the core of a massive star is mostly composed of iron, it can no longer sustain fusion reactions. This triggers its collapse and ultimately leads to a supernova explosion.
What energy transformation occurs during radioactive decay?
During radioactive decay, the energy transformation that occurs is the conversion of nuclear potential energy within the unstable atomic nucleus into various forms of energy such as heat, electromagnetic radiation (gamma rays), and kinetic energy of emitted particles (alpha and beta particles).
What is the family name of the group VIIIA elements?
I'm pretty sure that groups 3-12 (which includes 7) on the Periodic Table are classified as Metalloids.
In which region is Dalton GA located?
Dalton, GA is located in the southeastern region of the United States, specifically in the state of Georgia. It is part of the Appalachian region and is known for its prominence in the carpet industry.
Why hydration energy decreases down the group in periodic table?
Hydration energy decreases down the group in the periodic table because the size of the ions increases as you move down a group. When ions are larger, they are less strongly attracted to water molecules. Therefore, larger ions exhibit lower hydration energies compared to smaller ions.
What name given to group 7 on the periodic table?
Group 7 on the periodic table is called the halogens. This group includes elements like fluorine, chlorine, bromine, iodine, and astatine. Halogens are highly reactive nonmetals that readily form salts with metals.
What period is copper found in?
Copper smelting appears to have been developed independently in several parts of the world. In addition to its development in the Balkans by 5500 BC, it was developed in China before 2800 BC, in the Andes around 2000 BC, in Central America around 600 AD, and in West Africa around 900 AD.
What is the natural abundance of Ag-107 is 51.84 percent What is the natural abundance of Ag-109?
The natural abundance of Ag-109 can be calculated by subtracting the natural abundance of Ag-107 (51.84%) from 100%, since these two isotopes make up 100% of all naturally occurring silver isotopes. Thus, the natural abundance of Ag-109 is 48.16%.
The correct punctuation after "thousand" is a comma, not a period. For example, you would write "two thousand, five hundred" not "two thousand. five hundred".
Which element has atomic number 6?
There is no element with that atomic mass according to the periodic table, though the isotopes He-6, Be-6, and Li-6 are possible, but extremely rare.
Why lanthanoids and actinoids are placed at the bottom of periodic table?
Just so it can fit on one page
A zigzag course refers to a navigation method where a vehicle or person moves in a series of sharp turns or reversals in order to avoid obstacles or confuse pursuers. It is commonly used in military tactics, search and rescue operations, and skiing.
What is the example of the uses of covalent compounds as solvent in our daily life?
A covalent compound is a compound in which the atoms that are bonded share electrons rather than transfer electrons from one to the other. While ionic compounds are usually formed when metals bond to nonmetals, covalent compounds are formed when two nonmetals bond to each other.
Covalent compounds have the following properties (keep in mind that these are only general properties, and that there are always exceptions to every rule):
1) Covalent compounds generally have much lower melting and boiling points than ionic compounds.
As you may recall, ionic compounds have very high melting and boiling points because it takes a lot of energy for all of the + and - charges which make up the crystal to get pulled apart from each other. Essentially, when we have an ionic compound, we need to break all of the ionic bonds in order to make it melt.
On the other hand, when we have covalent compounds we don't need to break any bonds at all. This is because covalent compounds form distinct molecules, in which the atoms are bound tightly to one another. Unlike in ionic compounds, these molecules don't interact with each other much (except through relatively weak forces called "intermolecular forces"), making them very easy to pull apart from each other. Since they're easy to separate, covalent compounds have low melting and boiling points.
2) Covalent compounds are soft and squishy (compared to ionic compounds, anyway).
The reason for this is similar to the reason that covalent compounds have low melting and boiling points. When you hit an ionic compound with something, it feels very hard. The reason for this is that all of the ionic bonds which hold together the crystal tend to make it very inflexible and hard to move. On the other hand, covalent compounds have these molecules which can very easily move around each other, because there are no bonds between them. As a result, covalent compounds are frequently flexible rather than hard.
Think of it like this: Ionic compounds are like giant Lego sculptures. If you hit a Lego sculpture with your fist, it feels hard because all of the Legos are stuck very tightly to one another. Covalent compounds are more like those plastic ball pits they have at fast food playgrounds for little kids. While the balls themselves are held together very tightly (just like covalent molecules are held together tightly), the balls aren't really stuck to each other at all. As a result, when little kids jump into the ball pits they sink in rather than bouncing off.
3) Covalent compounds tend to be more flammable than ionic compounds.
The main reason that things burn is because they contain carbon and hydrogen atoms that can react to form carbon dioxide and water when heated with oxygen gas (that's the definition of a combustion reaction). Since carbon and hydrogen have very similar electronegativities, they are mostly found together in covalent compounds. As a result, more covalent compounds than ionic compounds are flammable.
There are a couple of exceptions to this rule. The first is with covalent compounds that contain neither carbon nor hydrogen. These tend not to burn, and if they do, they burn by mechanisms other than the classic combustion reaction. The other exception comes with ionic compounds referred to as "organic salts". These organic salts are ionic compounds in which the anion is basically a big covalent molecule containing carbon and hydrogen with just a very small ionic section. As a result, they burn even though they're technically ionic compounds.
4) Covalent compounds don't conduct electricity in water.
Electricity is conducted in water from the movement of ions from one place to the other. These ions are the charge carriers which allow water to conduct electricity. Since there are no ions in a covalent compound, they don't conduct electricity in water.
5) Covalent compounds are insoluble in water.
Naming Covalent Compounds
Covalent compounds are much easier to name than ionic compounds. Here's how you do it:
All covalent compounds have two word names. The first word typically corresponds to the first element in the formula and the second corresponds to the second element in the formula except that "-ide" is substituted for the end. As a result, HF is named "hydrogen fluoride", because hydrogen is the first element and fluorine is the second element.
If there is more than one atom of an element in a molecule, we need to add prefixes to these words to tell us how many are present. Here are the prefixes you'll need to remember:<center>Number of atoms
Prefix
</center>1
mono- (use only for oxygen)
2
di-
3
tri-
4
tetra-
5
penta-
6
hexa-
7
hepta-
8
octa-
Let's see how this works:
Examples:
P2O5 - this is named diphosphorus pentoxide, because there are two phosphorus atoms and five oxygen atoms.
CO - this is carbon monoxide (you need the "mono-" because there's only one oxygen atom).
CF4 - this is carbon tetrafluoride, because there's one carbon atom and four fluorine atoms.
