Electronegativity values decrease as you move across a period from left to right.

true

false

False because electronegativity tends to increase as you move from top to bottom through groups and from left to right for periods of the periodic table.

Explanation:

Electronegativity is the ability of an atom, within a molecule, to attract the electrons it shares with another atom. The electronegativity of an element is related to its ionization energy, which is the energy needed to start an electron to a gaseous atom, isolated and in fundamental state, and the electronic affinity, which energy exchanged when a neutral, gaseous atom, and in fundamental state, pick up an electron.

Given this, it can be said that the most electronegative elements have a tendency to capture electrons and form negative ions, because the values of their ionization energies and electronic affinity are high, that is, their electronegativity is high.

Both ionization energy and electronic affinity tend to increase as you move from top to bottom through groups and from left to right for periods of the periodic table.

Taking this into account, electronegativity, as it descends within the same group, the atomic radius increases and the ionization energy decreases, indicating that electrons are less attracted and therefore electronegativity decreases from top to bottom. And as you move through a period the atomic radius decreases and the ionization energy increases, making it increasingly difficult to extract an electron. Consequently the electronegativity increases from left to right.

In short, taking everything into account, it has the same tendency as electronic affinity and ionization energy in the periodic table. So electronegativity tends to increase as you move from top to bottom through groups and from left to right for periods of the periodic table.

To tell if a chemical reaction has occurred look at its color change, temperature change, Precipitate formation, gas production, and light emission.