An example of a physical change
is liquid water turning into vapor. Physical change is that it may involve a
change in phase but does not involve a change in molecular structure.
Answer:
The first element in the periodic table is hydrogen.
Explanation:
Hydrogen has an atomic number of one, making it the first element of the periodic table. The atomic number of an element is just the number of protons in the nucleus, so hydrogen has one proton. The neutrons and electrons do not affect the atomic number. After hydrogen with one proton comes helium with two, lithium with three, beryllium with four, and so on.
Answer:
4. gives the relative number of atoms of each element per formula unit
Explanation:
An empirical formula -
It refers to the formula which determined the simplest whole - number ratio of all the atoms in a given species , is referred to as an empirical formula .
In simple terms ,
It is he smallest formula of the whole number which when multiplied by some whole number gives the actual structure of the compound .
Hence , from the given information of the question ,
The correct option for empirical formula is 4.
<span>Chromium(II) sulfate
this is an ionic compound of a metal and a polyatomic ion.
chromium is a metal that can form more than one type of cation. In this case, the polyatomic ion name is sulfate and it has 2 negative charges. Then Cr has to have 2 positive charges.
then write the name of the metal followed by the charge of the ion between parenthesis and in roman numbers followed by the name of the polyatomic ion.</span>