Answer:
Barium has the same number of valence electrons as calcium
Explanation:
Valence electrons is the number of electrons of an atom on the outer shell.
Those valence electrons can participate in the formation of a chemical bond (if the outer shell is not closed); in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
<u>Calcium</u> is an atom, part of group 2, called the alkaline earth metals. The alkaline earth metals have 2 valence electrons.
<u>Sulfur </u>is part of a group 16, called the chalcogens or oxygen family. Those atoms have 6 valence electrons. They can form a bound with atoms of group 2 such as calcium, but do not have the same number of valence electrons.
<u>Potassium</u> is part of group 1, called the alkali metals or lithium family. Those atoms have 1 valence electrons. That means Potassium do not have the same number of valence electrons like calcium.
<u>Neon</u> is part of group 18, the noble gasses. Those are stable atoms, which means they have 8 valence electrons. They do not have the same number of valence electrons like Calcium.
<u>Barium</u> an atom, part of group 2, called the alkaline earth metals. The alkaline earth metals have 2 valence electrons. Calcium is also part of this group.
This means barium has the same number of valence electrons as Calcium.
Answer:
See explanation
Explanation:
The periodic table shows the atomic number and mass number of each element.
We know that the atomic number shows;
- The number of protons in the nucleus of the atom
- The number of electrons in the neutral atom of the element.
So we obtain the number of protons and electrons by looking at the atomic number shown in the periodic table.
We also know that;
Mass number = Number of protons + number of neutrons
Since number of protons = atomic number of the atom
Number of neutrons = Mass number - atomic number
Hence we obtain the number of protons by subtracting the atomic number from the mass number given in the periodic table.
The six electrons in the outermost shell allow selenium to have a variety of valence numbers.
The valence of selenium depends on which compound it is in. Selenium is very similar to sulfur. It may have a valence of 6.
EXAMPLE:
selenium hexafluoride SeF6, selenium trioxide SeO3
May have 4;
example
selenium tetrafluoride SeF4, selenium dioxide SeO2
MAy have 2;
example
selenium difluoride SeF2, selenium dichloride SeCl2
and may have -2;
example
hydrogen selenide H2Se
Answer:
A matter can not be created or destroyed in chemical reactions. In every chemical reactions, the same mass of matter must end up in the product as started in the reactants
