Elements on the Periodic Table in the same group have the same number of valence electrons. Since valence electrons are the only part of an atom that interacts with other atoms during a chemical reaction, you can make generalizations about elements' reactivity based upon what group they're in. Elements in the same group will behave similarly in chemical reactions even if they bear little resemblance to each other physically.
An element's mass number tells us the total number of protons and neutrons in its nucleus. It helps to determine the element's atomic mass and differentiate it from other isotopes of the same element.
atomic number tells us the number of protons and electrons in the given atom. As Atomic No. = no. of protons = No. of electrons
number of protons in the atoms tells us to what chemical element atoms belongs. in other words :different number of protons means different element. also protons together with neutrons make most of the atoms weight.
The atomic mass number tells us the total number of protons and neutrons in an atom's nucleus. It is used to determine the mass of an atom and is necessary for calculating the atomic weight of an element.
If you are referring to GROUP NUMBER when you say "Roman numeral above the group", it tells you the number of valence electrons, or the number of outermost electrons, with transition metals being the exception. For group number XII - XVIII the number of valence electrons is the group number minus 10 (minus 10 for the 10 transition groups).
An element's mass number tells us the total number of protons and neutrons in its nucleus. It helps to determine the element's atomic mass and differentiate it from other isotopes of the same element.
atomic number tells us the number of protons and electrons in the given atom. As Atomic No. = no. of protons = No. of electrons
The number of valence electrons tell us the group number of that element.
An element's atomic number tells us the number of protons in an atom of that element. It is used to uniquely identify the element and determine its placement on the periodic table. The atomic number also corresponds to the number of electrons in a neutral atom of that element.
The atomic number tells us the number of electrons and the number of protons., i.e. Atomic Number = Number of electrons = Number of Protons. The atomic mass tells the total number of particles in the nucleus, i.e. Atomic Mass = # of protons + number of neutrons. The Group number is the heading at the top of a column in the table. It tells the the outer electron configuration of the atom. This determines many chemical properties of the element.
The atomic number tells us the number of protons in the nucleus of an atom. It determines the element's identity and its place on the periodic table. Elements with different atomic numbers have different chemical properties.
The group to which the element belongs and, therefore, its chemical properties.
It tells us that:How many protons the atom hasHow many electrons the atom has (when it is in non-excited, ground state)It identifies the element itself
The group or family of an element in the periodic table tells us about the number of valence electrons an atom of that element has. This can provide information about the atom's reactivity and chemical properties. Different groups have similar characteristics due to their similar outer electron configurations.
In a molecular formula, the subscript tells us the number of atoms of the element that are present in one molecule of the compound. For instance,H2O tells us that there are two hydrogen and one oxygen atom per molecule of water. As for ionic compounds, it tells us the number of atoms present in one formula unit of the compound.
For elements it's the atomic number not the "Period Number." This number tells you how many protons a single atom of that element has in its nucleus. The "period number" is a dimensionless quantity used in fluid dynamics.
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.