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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
How do you find the concentration of 3.50g of potassium chromate in 100 ml water?
K2CrO4
Molarity (concentration) = moles of solute/Liters of solution (100 ml = 0.100 Liters )
Find moles K2CrO4 first.
3.50 grams = (1 mole K2CrO4/194.2 grams)
= 0.01802 moles K2CrO4
----------------------------------------------next
Molarity = 0.01802 moles K2CrO4/0.100 Liters
= 0.180 M K2CrO4
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BaF2 would be the best conductor in the pure liquid or molten state due to its ionic nature and ability to dissociate into ions. Other compounds listed are covalent in nature and do not dissociate into ions easily in the liquid or molten state, resulting in poor conductivity.
Why do the elements in the group 1 and 2 react with group 17?
Elements in group 1 have 1 electron in their outer shell. Group 7 electrons have 7 electrons in their outer shell. This means that the group 1 element needs to give its electron to the group 7 element so that they both have full outer shells, making them stable. By a school boy in yr. 10
Are reduction reactions and displacements the same thing?
Reduction reactions involve the gain of electrons by a molecule or atom. Displacement reactions involve the exchange of ions between two compounds. While reduction reactions can be involved in displacement reactions, they are not the same thing.
How many atoms are in 5 moles of lithium?
1 mole of lithium has 6.023 x 1023 atoms.
So 5 moles will have 30.115 x 1023 atoms
Did the periodic table come before the atomic model?
The periodic table came after the atomic model. The modern periodic table was developed based on the atomic structure proposed by scientists such as John Dalton, J.J. Thomson, Ernest Rutherford, and Niels Bohr. Mendeleev's periodic table was published in 1869, while the atomic model continued to evolve throughout the late 19th and early 20th centuries.
What element has 125 atomic number?
The element with atomic number 125 is unknown, as it has not been discovered or named yet. Elements beyond uranium (atomic number 92) are typically synthesized in laboratories and have very short half-lives.
What is the radioactive isotope in the periodic table?
A normal periodic table does not list isotopes, but elements, almost all of which occur in more than one isotope, and there is probably at least one radioactive isotope for every element. Instead of the periodic table, a table of nuclides is needed to answer this question.
Fluorine has the smallest atomic radius, while Francium has the largest atomic radius.
What instrument lead to the discovery of the neutron?
The invention of the cloud chamber by physicist Ernest Rutherford in 1911 led to the discovery of the neutron by James Chadwick in 1932. The cloud chamber allowed researchers to observe the tracks of subatomic particles, which helped Chadwick identify the previously unknown neutron.
Yes, but they lose the 'identity' of the element when they are divided.
Atoms were once thought to be indivisible units of an element - the smallest thing that retained the characteristics of an element. The word comes from the Greek for indivisible/uncuttable ~ a+ temnein.
It is now known that atoms contain protons, neutrons and electrons and that even these are composed of smaller particles called quarks.
What is one part oxygen and two parts carbon?
The formula should be C2O, but there is no compound that way.
The other way around (one carbon and two oxygen) is known. It is carbon dioxide or CO2.
What is a large table that scientists use to find out information about metals and other elements?
The periodic table of elements
What elements are most likely to give up electrons rather than share electrons?
Elements with small atomic radii and low ionization energies are more likely to give up electrons rather than share them. These typically include metals such as alkali metals and alkaline earth metals on the left side of the periodic table.
Is platinum a metal or non-metals or metalloid?
Platinum is a metal. It is a rare and precious metal known for its resistance to corrosion and high value in various industries such as jewelry, electronics, and automotive.
What is the boiling point and the freezing point of neon?
Living on a water table like this is never an easy situation. There are a few different options that would all definitely suffice for this particular occasion, though I would recommend vinyl: http://knol.google.com/k/new-basement-flooring-options#
How many elements are there in the first period of periodic table?
There are 2 elements in the first period of the periodic table: Hydrogen and Helium.
What is the atomic number on a table that tells us how many of what are in an atom of the element?
The atomic number of an elemnt tells you how many protons are in the nucleus and therefore how many electrons thare are in a neutral atom.
The mass number is the toal of protons and neutrons.
What is hcn in the periodic table?
HCN stands for hydrogen cyanide, which consists of hydrogen, carbon, and nitrogen atoms. Hydrogen is in the first column (group 1) of the periodic table, carbon is in the fourth column (group 14), and nitrogen is in the fifteenth column (group 15).
How many rare earth metals are listed on the table?
There are 6 rare metals they are Helium, Neon, Krypton , Argon, Xenon and radon in the periodic table.
What is element 20 on the periodic table?
Element 20 on the periodic table is calcium. It is a soft gray alkaline earth metal that is essential for living organisms. Calcium plays a crucial role in various bodily functions, such as bone structure, muscle contraction, and nerve function.
How do mendeelevs periodic table and todays periodic table differ?
When Mendeleev's periodic table was devised, some elements hadn't been discovered yet. Therefore, there had to be gaps in it or the table would be rendered incorrect.
The rule of similarities states that the elements within a specific period/column are similar in a way and have the same number of electrons in the outer shell. E.g. Period 1 (alkali metals) react strongly with both air and water, have to be stored in oil, and are very alkali, hence the name.
Mendeleev used this rule to construct the periodic table. The amazing thing is, he guessed where elements were missing and left gaps. He even estimated their atomic masses!
In short, Mendeleev's periodic table had some bits missing. (e.g. technetium, discovered in 1936, a whole 65 years after Mendeleev's table was devised in 1871)
P.S. It's Mendeleev, not Mendeelev.
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