Unit 2 Vocabulary Periodic Trends

​PERIODIC TRENDS 2.7
VOCABULARY

By Ashley Wiehl

CORE ELECTRONS
electrons located in inner shells

Multiple Choice

Core electrons are you go down a group

• increases.

• decreases.

• stays the same.

Multiple Choice

Core electrons are you go across a period

• increases.

• decreases.

• stays the same.

VALANCE ELECTRONS
eletrons located on the outermost shell

Multiple Choice

Valence electrons as you go down a group

• increases.

• decreases.

• stays the same.

Multiple Choice

Valence electrons as you go across a period

• increases.

• decreases.

• stays the same.

ISOELECTRONIC
two atoms having the same electron configuration

Multiple Choice

What is the example of species that are isolectronic?

• Li⁺ and H⁺

• S^2- and O^2-

• Li⁺ and He

• F^- and Cl^-

Multiple Choice

What is the example of species that are isolectronic?

• Na⁺ and Si⁴⁺

• Na⁺ and Cl^-

• Mg²⁺ and Al ⁺

• S^2- and O^2-

NUCLEAR CHARGE
the positive pull of the nucleus

EFFECTIVE NUCLEAR CHARGE
= #p+ - #core e-

Multiple Choice

When Z_eff increases, the nucleus attraction

towards electrons become

• Weaker

• Stronger

• Remain the same

Multiple Choice

The effective nuclear charge of magnesium is

• +1

• +2

• +12

• +24

SHIELDING
protection of the valence electrons from the nuclear charge

Multiple Choice

What is electron shielding?

• Inner electrons shield the valence shell from protons

• Valence electrons shield the inner electrons from atoms

• Electrons build an impenetrable shield against neutrons

• Electrons are used to shield a radioactive isotope

Multiple Choice

Which element has the most electron shielding?

• O

• S

• Cu

• Se

Multiple Choice

Which electrons are responsible for shielding?

• Valence electron

• Core electrons

• s- and p- orbital electrons

• All electrons in the atom

IONIZATION ENERGY
amount of energy required to remove a valence electron

Multiple Choice

Which of the following elements would you expect to have the lowest ionization energy, and why?

• Helium (He), because it is a noble gas

• Francium (Fr), because it is at the bottom of Group 1

• Fluorine (F), because it is highly electronegative

• Carbon (C), because it is in the middle of a period

Multiple Choice

Based on the graph, rank the first 5 group 2 elements in decreasing order of first ionization energy.

• Be, Mg, Ca, Sr

• Ba, Sr, Ca, Mg

• Mg, Ca, Sr, Ba

• Ca, Sr, Ba, Mg

ATOMIC RADII
the size of the whole atom

Multiple Choice

What happens to atomic radius across a period?

• the atoms get bigger because the nucleus is bigger as more protons are added

• the atoms get bigger because there are more ve-

• the atoms get smaller because with more attraction to the extra protons, the e- cloud moves closer to the nucleus

PHOTOELECTRON SPECTROSCOPY (PES)
a graph visualizing electron configuration

Multiple Choice

The PES spectrum below is for the element _______________.

• O

• Ne

• N

• F

Multiple Choice

What is the electron configuration for this PES graph?

• 1s²2s²2p⁶3s²3p²

• 1s²2s²2p⁶3s²3p¹

• 1s²2s²2p⁶3s²3p³

• 1s²2s²2p⁶3s²

PES GRAPHS

Multiple Choice

The complete photoelectron spectrum for an element is shown above. Which of the following observations would provide evidence that the spectrum is consistent with the atomic model of the element?

• A neutral atom of the element contains exactly two electrons.

• The element does not react with other elements to form compounds.

• In its compounds, the element tends to form ions with a charge of +1.

• In its compounds, the element tends to form ions with a charge of +3.

Multiple Choice

How many peaks would you expect to see on the PES graph for potassium? (*Hint: write out the electron configuration first.)

• 5

• 6

• 7

• 8

ELECTRONEGATIVITY
the tendency to attract electrons

ELECTRON AFFINITY
the amount of energy released when an atom gains an electron