Trend Starters
What do elements in the same group have in common?
Same number of valence electrons
What happens to atomic radius as you move from left to right across a period?
Atomic radius decreases
What are the electrons in the outermost energy level called?
Valence electrons
Which type of elements tend to lose electrons during reactions?
Metals
Rank these elements from largest atomic radius to smallest:
Na, Cl, Al
Na > Al > Cl
How many energy levels does an element in Period 4 have?
4 energy levels
Which periodic trend describes how strongly an atom attracts electrons in a bond?
Electronegativity
DOUBLE JEOPARDY!!
What term describes the net positive charge experienced by valence electrons?
Effective nuclear charge
Which group contains the most reactive metals?
Alkali metals (Group 1)
Which element would require the most energy to remove an electron?
K, Ca, Br, or Ne
Ne
What type of elements are located along the stair-step line on the periodic table?
Metalloids
Why does atomic radius increase as you move down a group?
Additional energy levels increase the distance between the nucleus and valence electrons.
What is the shielding effect?
Inner electrons block the attraction between the nucleus and outer electrons.
Which type of elements tend to gain electrons during chemical reactions?
Nonmetals
Which element would most likely have low ionization energy and high reactivity?
Cs, F, Ne, or Ar
Cs
Which block of the periodic table contains Groups 1 and 2?
s-block
Why does ionization energy generally increase across a period?
Effective nuclear charge increases, so electrons are held more tightly.
An atom has the electron configuration: 1s² 2s² 2p⁶ 3s² 3p³
How many valence electrons does it have?
Double Jeopardy!!
Why are halogens highly reactive?
They need one electron to complete their valence shell.
Why are noble gases generally unreactive?
They have full valence electron shells.
DOUBLE JEOPARDY!!
The repeating pattern of chemical and physical properties of elements when arranged by increasing atomic number.
The Periodic Law
Which element would have the highest electronegativity?
Sodium, chlorine, calcium, or aluminum
chlorine
An element in Group 16 will have this number of dots in its electron dot structure.
They have 6 valence electrons.
Why are alkali metals very reactive?
They have one valence electron that is easily lost.
FINAL JEOPARDY!!
Explain why fluorine is more reactive than iodine.
Fluorine has a smaller atomic radius and stronger effective nuclear charge, so it attracts electrons more strongly.