As you move from left to right across any period what are two constants (with few exceptions) that you notice? *perodic table*

Atomic number

Atomic radius

Electronegativity  etc

Step-by-step explanation:

The periodic table is a tabular display of chemical element . The periodic table is divided into periods and groups. There are different physical or chemical properties one may notice as you move across the periodic table or down the group .  The major properties are atomic numbers, ionization energy, atomic radius, metallic, non metallic , electron affinity and electronegativity.

Atomic number of an element is the number of proton in an element . During bonding the electron number may change but he proton number is constant and remains unchanged. The atomic number increases from left to right across the periodic table.

Ionization energy is the energy required to remove the most loosely bound electron of an atom . The more tightly bound an electron of an atom is will increase the amount of energy required to lose the electron. This means the ionization energy will increase. Ionization energy increases as you go across a period from left to right.

Electronegativity is the measure of an atom’s tendency to attract a bonding pair of electrons. Electronegativity increases as you move from left to right across the period.

Atomic radius is defined as half the distance between the nuclei of 2 identical atoms bonded closely together.  Atomic radius across a period from left to right decreases.

Electron affinity and metallic character increases across the period from left to right.