Question

1. which element has the greater atomic radius? (circle)

a. as or br b. n or as c. li or ne

1. which element has the greater ionization energy? (circle)

a. k or kr b. li or k c. s or se

1. which element has the greater electronegativity? (circle)

a. p or cl b. f or cl c. mg or ba

1. what element on the periodic table is the most electronegative? do not count noble gases because they generally do not bond with other elements.
2. list the physical and chemical properties of metals and nonmetals.
3. what are the defining characteristics of a metalloid? list the metalloids.
4. give an example of an element for each of the following 10 categories:

alkali metals actinides noble gases
alkaline earth metals other metals other nonmetals
transition metals metalloids halogens
lanthanides

1. list the characteristics of the alkali metals.
2. list the characteristics of the alkaline earth metals.
3. list the characteristics of the transition metals.
4. list the characteristics of the halogens.
5. list the characteristics of the noble gases.

Explanation:

Step1: Recall atomic - radius trends

Atomic radius increases down a group and decreases across a period.
- For a. As and Br are in the same period. As is to the left of Br, so As has a greater atomic radius.
- For b. N is in period 2 and As is in period 4. As has more electron - shells, so As has a greater atomic radius.
- For c. Li and Ne are in the same period. Li is to the left of Ne, so Li has a greater atomic radius.

Step2: Recall ionization - energy trends

Ionization energy increases across a period and decreases down a group.
- For a. K is a metal and Kr is a noble gas in the same period. Kr has a greater ionization energy.
- For b. Li and K are in the same group. Li is higher up, so Li has a greater ionization energy.
- For c. S and Se are in the same group. S is higher up, so S has a greater ionization energy.

Step3: Recall electronegativity trends

Electronegativity increases across a period and decreases down a group.
- For a. P and Cl are in the same period. Cl is to the right of P, so Cl has a greater electronegativity.
- For b. F and Cl are in the same group. F is higher up, so F has a greater electronegativity.
- For c. Mg and Ba are in the same group. Mg is higher up, so Mg has a greater electronegativity.

Step4: Identify the most electronegative element

Fluorine (F) is the most electronegative element on the periodic table (excluding noble gases).

Step5: List properties of metals and non - metals

**Metals**: Physically, they are good conductors of heat and electricity, malleable, and ductile. Chemically, they tend to lose electrons in chemical reactions.
**Non - metals**: Physically, they are poor conductors of heat and electricity (except some like graphite), brittle. Chemically, they tend to gain electrons in chemical reactions.

Step6: Define metalloids and list them

Metalloids have properties intermediate between metals and non - metals. They are boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po), and astatine (At).

Step7: Give element examples

- **Alkali metals**: Sodium (Na)
- **Alkaline earth metals**: Calcium (Ca)
- **Transition metals**: Iron (Fe)
- **Lanthanides**: Cerium (Ce)
- **Actinides**: Uranium (U)
- **Other metals**: Aluminum (Al)
- **Metalloids**: Silicon (Si)
- **Halogens**: Chlorine (Cl)
- **Noble gases**: Argon (Ar)
- **Other non - metals**: Phosphorus (P)

Step8: List alkali metal characteristics

Alkali metals are soft, silvery - white, highly reactive metals. They have one valence electron, low melting and boiling points, and react vigorously with water to form hydroxides and hydrogen gas.

Step9: List alkaline earth metal characteristics

Alkaline earth metals are harder, denser, and have higher melting points than alkali metals. They have two valence electrons and are less reactive than alkali metals but still quite reactive, forming oxides and hydroxides.

Step10: List transition metal characteristics

Transition metals have variable oxidation states, form colored compounds, are good conductors of heat and electricity, and are often used as catalysts.

Step11: List halogen characteristics

Halogens are highly reactive non - metals. They have seven valence electrons, exist as diatomic molecules in their elemental form (e.g., \(F_2\), \(Cl_2\)), and form salts when they react with metals.

Step12: List noble gas characteristics

Noble gases are colorless, odorless, monatomic gases. They have a full outer electron shell (except helium which has 2 electrons), and are very unreactive due to their stable electron configuration.

Answer:

1. a. As; b. As; c. Li
2. a. Kr; b. Li; c. S
3. a. Cl; b. F; c. Mg
4. Fluorine (F)
5. Metals: Good heat/electricity conductors, malleable, ductile; lose electrons. Non - metals: Poor heat/electricity conductors, brittle; gain electrons.
6. Properties intermediate between metals and non - metals. Boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po), astatine (At)
7. Sodium (Na); Calcium (Ca); Iron (Fe); Cerium (Ce); Uranium (U); Aluminum (Al); Silicon (Si); Chlorine (Cl); Argon (Ar); Phosphorus (P)
8. Soft, silvery - white, highly reactive, one valence electron, low melting/boiling points, react with water to form hydroxides and hydrogen.
9. Harder, denser, higher melting points than alkali metals, two valence electrons, less reactive than alkali metals but still reactive.
10. Variable oxidation states, form colored compounds, good conductors, often used as catalysts.
11. Highly reactive non - metals, seven valence electrons, diatomic in elemental form, form salts with metals.
12. Colorless, odorless, monatomic, full outer electron shell, very unreactive.