* Atomic Number: The number of protons in an atom's nucleus is called its atomic number. As you move across a period, the atomic number increases by one for each element.
* Protons: Protons are positively charged particles.
* Nuclear Charge: The overall positive charge of the nucleus is called the nuclear charge. Since the number of protons increases, the nuclear charge also increases.
Example:
* Lithium (Li): Atomic number 3, 3 protons, nuclear charge +3
* Beryllium (Be): Atomic number 4, 4 protons, nuclear charge +4
* Boron (B): Atomic number 5, 5 protons, nuclear charge +5
This increasing nuclear charge has significant effects on the chemical behavior of elements across a period. For example:
* Electronegativity: The ability of an atom to attract electrons in a bond increases as nuclear charge increases.
* Ionization Energy: The energy required to remove an electron from an atom increases as nuclear charge increases.
Let me know if you have any other questions!
