Question

Which two trends increase when one moves across a period from left to right?

Answer 1

Answer is: a) ionization energy and electronegativity.

1) The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).  

Barium, potassium and arsenic are metals (easily lost valence electrons), chlorine is nonmetal (easily gain electrons).

Alkaline metals (far left in Periodic table) have lowest ionizations energy and easy remove valence electrons (one electron), earth alkaline metals (next right to alkaline metals) have higher ionization energy than alkaline metals, because they have two valence electrons.  

Nonmetals are far right in the main group and they have highest ionization energy, because they have many valence electrons.  

2) Electronegativity (χ) is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.  

Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.  

Nonmetals hava higher electronegativity than metals and metalloids.

3) The atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.

Answer 2

Ionization energy and electronegativity are the two trends than increase when one moves across a period from left to right.

Further Explanation

Ionization energy

• Ionization energy is the energy required to remove outermost electrons from the outermost energy level. Energy is required to remove an electron from an atom.
• The closer an electron is to the nucleus the more energy is required, since the electron is more tightly bound to the atom thus making it more difficult to remove, hence higher ionization energy.
• Ionization energy increases across the periods and decreases down the group from top to bottom.  
• Additionally, the ionization energy increases with subsequent removal of a second or a third electron.

First ionization energy  

• This is the energy required to remove the first electron from the outermost energy level of an atom.
• Energy needed to remove the second electron to form a divalent cation is called the second ionization energy.

Trends in ionization energy  

Down the group(top to bottom)

• Ionization energy decreases down the groups in the periodic table from top to bottom.
• It is because as you move down the group the number of energy levels increases making the outermost electrons get further from the nucleus reducing the strength of attraction to the nucleus.
• This means less energy will be required compared to an atoms of elements at the top of the groups.

Across the period  (left to right)

• Ionization energy increases across the period from left to right.
• This can be explained by an increase in nuclear energy as extra protons are added to the nucleus across the period increasing the strength of attraction of electrons to the nucleus.
• Consequently, more energy is needed to remove electrons from the nucleus.

Electronegativity

• Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.  
• Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.  
• Non-metals have higher electronegativity than metals and metalloids.

Atomic radius

• The atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.

Keywords: Ionization energy, electronegativity

Learn more about

• Ionization energy: brainly.com/question/5880605
• Trend in ionization energy: brainly.com/question/5880605
• First ionization energy: brainly.com/question/5880605
• Electronegativity: brainly.com/question/4283174
• Trends in electronegativity: brainly.com/question/4283174

Level: High school  

Subject: Chemistry  

Topic: Periodic table and chemical families  

Sub-topic: Ionization energy and electronegativity