Question

1. two-thirds of the modern periodic table is made up of metals. so when we think about the phrase \metallic properties\ we think about how strongly these metals demonstrate these properties. similar to electronegativity, ionization energy and effective nuclear charge, metallic properties is a trend. (1) reaction to water is a chemical characteristic that mendeleev used to characterize elements.

a. which elements showed the greatest reaction to water?
b. what observations did you make that tells you this element had the greatest reaction to water?
c. where on the periodic table is this element located?
i. group:
ii. period:
d. which element had the least reaction to water?
e. what observations did you make that tells you this element had the greatest reaction to water?
f. where on the periodic table is this element located?
i. group:
ii. period:
(2) conductivity is a physical characteristic that can be used to identify metallic properties.
a. which elements showed the greatest reaction to water?
b. what observations did you make that tells you this element had the greatest reaction to water?
c. where on the periodic table is this element located?
i. group:
ii. period:
d. which element had the least reaction to water?
e. what observations did you make that tells you this element had the greatest reaction to water?
f. where on the periodic table is this element located?
i. group:
ii. period:

Explanation:

Part (1) - Reaction to Water

a. Greatest Reaction to Water

Alkali metals (Group 1) like Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) show increasing reactivity with water down the group. Cesium (Cs) or Potassium (K) (often K or Na in basic studies) have vigorous reactions. For basic understanding, Sodium (Na) or Potassium (K) are common examples. Sodium reacts rapidly, fizzing, moving on water, sometimes melting. Potassium reacts more vigorously, with a flame (lilac color).

b. Observations for Greatest Reaction

For Potassium (K): It reacts very quickly, skims across water surface, produces a lilac flame (due to heat of reaction igniting hydrogen gas), vigorous fizzing (H₂ gas production: \( 2K + 2H_2O
ightarrow 2KOH + H_2 \)). For Sodium (Na): Rapid fizzing, moves rapidly, melts (low melting point) due to exothermic reaction.

c. Location of Most Reactive (e.g., Potassium)

i. Group: 1 (Alkali Metals)
ii. Period: 4 (Potassium is in Period 4; Sodium in Period 3, Cesium in Period 6)

d. Least Reaction to Water

Alkaline earth metals (Group 2) are less reactive than Group 1. Among common metals, Magnesium (Mg) reacts slowly with cold water (faster with steam), or Beryllium (Be) which barely reacts. Copper (Cu), Silver (Ag), Gold (Au) (transition metals) are unreactive with water.

e. Observations for Least Reaction

For Copper (Cu): No visible reaction with cold water. Magnesium: Very slow bubbling (if clean) or no reaction with cold water (reacts with steam: \( Mg + H_2O(g)
ightarrow MgO + H_2 \)).

f. Location of Least Reactive (e.g., Copper)

i. Group: 11 (Transition Metals, Group IB)
ii. Period: 4

Part (2) - Conductivity (Note: Question has typo, "greatest reaction to water" should be "greatest conductivity" likely)

a. Greatest Conductivity

Metals have high conductivity. Alkali metals (Group 1) and transition metals (like Copper, Silver, Gold) are good conductors. Silver (Ag) is the best conductor, followed by Copper (Cu), Gold (Au), Aluminum (Al).

b. Observations for Conductivity

Conductivity is measured by ability to carry electric current. Metals allow current flow, non - metals (like Carbon in graphite is conductive, but non - metal) or insulators (like Sulfur) do not. For metals, if tested with a conductivity apparatus, the bulb lights up brightly.

c. Location of Most Conductive (e.g., Copper)

i. Group: 11 (Transition Metals)
ii. Period: 4

d. Least Conductivity

Non - metals: Sulfur (S), Phosphorus (P), Carbon (diamond, an insulator). Diamond (C, Group 14, Period 2) is an insulator.

e. Observations for Least Conductivity

No current flow (bulb does not light), or very low resistance.

f. Location of Least Conductive (e.g., Sulfur)

i. Group: 16 (Chalcogens)
ii. Period: 3

Answer:

s (Sample for Key Parts):

(1)a. Potassium (K) (or Sodium (Na), Cesium (Cs))

(1)b. Vigorous fizzing, flame (K), rapid movement, melting (Na)

(1)c i. 1; ii. 4 (for K)

(1)d. Copper (Cu) (or Magnesium (Mg) for slow, Au/Ag)

(1)e. No visible reaction (Cu) or slow bubbling (Mg cold water)

(1)f i. 11; ii. 4 (for Cu)

(2)a. Silver (Ag) (or Copper (Cu))

(2)b. Bright bulb in conductivity test

(2)c i. 11; ii. 5 (for Ag, Period 5)

(2)d. Sulfur (S) (or Diamond (C))

(2)e. Bulb does not light

(2)f i. 16; ii. 3 (for S)

(Note: Answers depend on context (e.g., lab experiments with common metals like Na, K, Mg, Cu). Adjust based on typical classroom demonstrations.)