Unit 2 Vocabulary Periodic Trends

increases.

decreases.

stays the same.

increases.

decreases.

stays the same.

increases.

decreases.

stays the same.

increases.

decreases.

stays the same.

Li⁺ and H⁺

S^2- and O^2-

Li⁺ and He

F^- and Cl^-

Na⁺ and Si⁴⁺

Na⁺ and Cl^-

Mg²⁺ and Al ⁺

S^2- and O^2-

Weaker

Stronger

Remain the same

+1

+2

+12

+24

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

O

S

Cu

Se

Valence electron

Core electrons

s- and p- orbital electrons

All electrons in the atom

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

Be, Mg, Ca, Sr

Ba, Sr, Ca, Mg

Mg, Ca, Sr, Ba

Ca, Sr, Ba, Mg

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

O

Ne

N

F

1s²2s²2p⁶3s²3p²

1s²2s²2p⁶3s²3p¹

1s²2s²2p⁶3s²3p³

1s²2s²2p⁶3s²

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.

5

6

7

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