So, when the atomic number increases, the mass number of the isotopes is higher (though they are different isotopes), and so the relative atomic mass will increase. Since this occurs as you go down a group, the atomic mass increases as you go down a group.
Why does atomic mass decrease across a period?
Within a period, protons are added to the nucleus as electrons are being added to the same principal energy level. These electrons are gradually pulled closer to the nucleus because of its increased positive charge. Since the force of attraction between nuclei and electrons increases , the size of the atoms decreases.
Does the atomic mass increase as you move across a period?
As you move across a period, the atomic mass increases because the atomic number also increases. When the atomic number increases, this means that there are more protons and neutrons that add to the atomic mass of an atom.
Do atomic masses increase or decrease as you move from left to right across the 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.
Does atomic mass always increase from left to right?
Explanation: As you go from left to right in the Periodic Table, you are adding more protons and neutrons to the nuclei. ... Therefore, atomic mass increases from left to right and from top to bottom of the Periodic Table.
Why does atomic size increase down a group and decrease left to right?
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 . ... Down a group, atomic radius
Which element is most essential for life?
Oxygen . Oxygen is the most abundant element
What happens when you move across a period on the periodic table?
Elements in the same period have the same number of electron shells; moving across a period (so progressing from group to group), elements gain electrons and protons and become less metallic . This arrangement reflects the periodic recurrence of similar properties as the atomic number increases.
What happens to the atomic number as you move across a period?
The atomic number increases moving left to right across a period and subsequently so does the effective nuclear charge. Therefore, moving left to right across a period the nucleus has a greater pull on the outer electrons and the atomic radii decreases.
What happens to the atomic radius as you move across a period from left to right?
Moving from left to right across a period, the atomic radius decreases . The nucleus of the atom
What is the rule of atomic mass?
To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons . ... You can see from the periodic table that carbon has an atomic number of 6, which is its number of protons. The atomic mass of the atom is the mass of the protons plus the mass of the neutrons, 6 + 7, or 13.
What is the trend for atomic mass?
The atomic number increases across a period and down the group or family. The atomic mass generally increases with atomic number with a few exceptions.
What happens to the mass as you move left to right across a period and down a row?
Explanation: As you go from left to right in the Periodic Table, you are adding more protons and neutrons to the nuclei . ... Therefore, atomic mass increases from left to right and from top to bottom of the Periodic Table.
Why do both atomic size and ionic size increase as you move down a group?
Basically, as we move down the periodic table, the size of the nucleus increases , and concomitantly more electrons are present to “shield” the valence electrons from the charge. ... If there are many electrons, its harder to rope them up via electron charge than when there are less.
How do atomic radii vary in a group and period?
In general, atomic radius decreases across a period and increases down a group . ... Down a group, the number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital. This results in a larger atomic radius.
Why does atomic size decreases as we move from left to right along a period in periodic table?
Atomic radius
