In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present). The number of protons determines how many electrons surround the nucleus, and it is the arrangement of these electrons that determines most of the chemical behavior of an element.

In a periodic table arranged in order of increasing atomic number, elements having similar chemical properties naturally line up in the same column (group). For instance, all of the elements in Group 1A are relatively soft metals, react violently with water, and form 1+ charges; all of the elements in Group 8A are unreactive, monatomic gases at room temperature, etc. In other words, there is a periodic repetition of the properties of the chemical elements with increasing mass.

Atomic Number of Bromine. Bromine is a chemical element with atomic number 35 which means there are 35 protons and 35 electrons in the atomic structure. The chemical symbol for Bromine is Br. Atomic Mass of Bromine. Atomic mass of Bromine is 79.904 u.

1. Bromine: Symbol: Br: Atomic Number: 35: Atomic Mass: 79.904 atomic mass units: Number of Protons: 35: Number of Neutrons: 45: Number of Electrons: 35: Melting Point-7.2° C: Boiling Point. Approximately 500 million kilograms of bromine are produced worldwide in a year. Common Uses: Brominated vegetable oil; Citrus flavored soft drinks.
2. Atomic Number: 35: Atomic Symbol: Br: Atomic Weight: 79.904: Electron Configuration. Little bromine is extracted today from seawater, which contains only about 85.
3. Bromine (Br) Atomic Data for Bromine (Br) Atomic Number = 35 Atomic Weight = 79.904 Reference E95.

Br-80 Atomic Number

In the original periodic table published by Dimitri Mendeleev in 1869, the elements were arranged according to increasing atomic mass— at that time, the nucleus had not yet been discovered, and there was no understanding at all of the interior structure of the atom, so atomic mass was the only guide to use. Once the structure of the nucleus was understood, it became clear that it was the atomic number that governed the properties of the elements.