Question

1. which of the following is an alkaline earth metal?

a. potassium
b. barium
c. chlorine
d. nickel

1. (sc.912.p.8.5) which family of elements does neon belong to?

a. transition metals
b. metalloids
c. nonmetals
d. noble gases

1. who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing elements?

a. dmitri mendeleev
b. john dalton
c. antoine lavoisier
d. henry moseley

1. which column(s) contain soft metals?

a. 1a
b. 2a
c. both 1a and 2a
d. neither 1a or 2a

1. compared to the alkali metals, the alkaline earth metals

a. have less valence electrons
b. are softer metals
c. are more reactive
d. are less reactive
stop
you have reached the end of this section.

Explanation:

• Question 16: Alkaline earth metals are in group 2A of the periodic table. Barium (Ba) is in group 2A. Potassium (K) is an alkali metal (group 1A), chlorine (Cl) is a non - metal (group 17), and nickel (Ni) is a transition metal.
• Question 17: Neon (Ne) has a full valence shell and is in group 18 of the periodic table, which is the noble gases group. Transition metals are in the d - block, metalloids have properties between metals and non - metals, and non - metals are in various groups (not group 18 for Ne).
• Question 18: Dmitri Mendeleev arranged elements by atomic mass and predicted properties of missing elements. John Dalton proposed the atomic theory, Antoine Lavoisier is known for work in chemistry like the law of conservation of mass, and Henry Moseley arranged elements by atomic number.
• Question 19: Alkali metals (group 1A) are soft metals. Alkaline earth metals (group 2A) are also relatively soft compared to many other metals.
• Question 20: Alkali metals (group 1A) have 1 valence electron, alkaline earth metals (group 2A) have 2 valence electrons (so A is wrong). Alkali metals are softer than alkaline earth metals (so B is wrong). Alkali metals are more reactive than alkaline earth metals (so C is wrong). Alkaline earth metals are less reactive than alkali metals.

Answer:

1. B. Barium
2. D. Noble Gases
3. A. Dmitri Mendeleev
4. C. Both 1A and 2A
5. D. are less reactive