Table of Contents

What is the trend of atomic size on the periodic table?

Atomic size gradually decreases from left to right across a period of elements. This is because, within a period or family of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus, making it more positively charged.

How does the atomic mass change in a periodic table?

Explanation: As you go from left to right in the Periodic Table, you are adding more protons and neutrons to the nuclei. The atoms in the rows further down have even more protons and nucleons. Therefore, atomic mass increases from left to right and from top to bottom of the Periodic Table.

What is the trend for atomic number?

Group Trend The atomic radius of atoms generally increases from top to bottom within a group. As the atomic number increases down a group, there is again an increase in the positive nuclear charge. However, there is also an increase in the number of occupied principle energy levels.

What does the atomic mass on the periodic table tell you?

The mass number tells us the number (the sum of nucleons) of protons and neutrons in the nucleus of an atom. The atomic number uniquely identifies a chemical element. In an atom of neutral charge, atomic number is equal to the number of electrons.

What 2 things does the atomic number represent?

The atomic number is the number of protons in an atom, and isotopes have the same atomic number but differ in the number of neutrons.

How is an atomic number determined?

Neutral atoms of each element contain an equal number of protons and electrons. The number of protons determines an element’s atomic number and is used to distinguish one element from another. Together, the number of protons and the number of neutrons determine an element’s mass number.

What is the difference between atomic mass and atomic number?

Atomic mass is associated with the number of neutrons and protons that are present in a particular nucleus of an element. Atomic number is usually the number of protons present in an element’s nucleus. It is the average weight of an element. It is the total number of nucleons in the atom’s nucleus.

How is an element determined?

Explanation: An element is defined by its number of protons. Varying the number of neutrons will change the isotope of an element and varying the number of electrons will create an ion, but changing the number of protons changes the identity of the element itself.

Why isn’t the atomic mass a whole number?

Atomic mass is never an integer number for several reasons: The atomic mass reported on a periodic table is the weighted average of all the naturally occuring isotopes. Being an average it would be most unlikely to be a whole number. The mass of an individual atom in atomic mass units is the mass relative to carbon-12.

Why are mass numbers always whole?

The mass number is always a whole number; because it is a count of the particles. It differs from the exact mass of the atom in atomic mass units, amu, which is often known and expressed to six decimal places.

Are atomic numbers always whole?

Atomic number is simply the count of protons in an atom’s nucleus, so it is always a whole number.

2021-06-17