What is the small number at the top of an element?
The little number you see to the right of the symbol for an element is called a subscript. That number indicates the number of atoms of that element present in the compound. When balancing an equation, you can change the coefficients but not the subscripts.
What are the 3 numbers on the periodic table?
The Elements, sorted by Atomic Number
| Atomic Number | Symbol | Name |
|---|---|---|
| 2 | He | Helium |
| 3 | Li | Lithium |
| 4 | Be | Beryllium |
| 5 | B | Boron |
What does the decimal numbers mean on the periodic table?
atomic mass
Though individual atoms always have an integer number of atomic mass units, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element.
What do the column numbers on the periodic table mean?
Many periodic tables list numbers for element groups, which are columns of the periodic table. The elements in a group share the same number of valence electrons and thus have many common chemical and physical properties.
What does 2+ mean on an element?
If the number of electrons is less than the number of protons, the particle is a positive ion, also called a cation. A carbon atom with 4 electrons is therefore symbolized C 2+ , and a carbon atom with 3 electrons is symbolized C 3+ .
How do you read a periodic table?
Read the periodic table from top left to bottom right. The elements are ordered by their atomic numbers, which increase as you move across and down the periodic table. The atomic number is how many protons the element’s atom possesses.
What does +3 mean on an element?
The iron ion Fe3+, for example, has an oxidation number of +3 because it can acquire three electrons to form a chemical bond, while the oxygen ion O2− has an oxidation number of −2 because it can donate two electrons.
Is it +2 or 2+ charge?
Charge numbers in nuclear and hadron physics In chemistry, the same charge numbers are usually indicated as superscript “+2” or “−2”.
Who is the smallest element?
helium
The element which has the smallest atomic mass is Hydrogen (H), which has a proton and an electron. The atomic radius decreases as we move from left to right along the period. And The atomic radius increases down the group. Thus, helium is the smallest element, and francium is the largest.