5. The Modern Periodic Law states the properties of elements vary periodically
with atomic number. Who introduced this concept?
A. Dmitri Mendeleev
C. Lothar Meyer
B. John Newlands
D. Henry Moseley
6. A reaction does not always happen between a metal and a compound. There
is an existing definite order of reactivity existing among metals and hydrogen
according to their ability to displace one another. Which of the following
elements can replace hydrogen in the compound HCI (Hydrochloric Acid)?
A. Cu
C. Ag
B. Al
D. Au
7. Group 18 composed of Halogens. This group consists of salt-forming
nonmetals. Which of the following elements DOES NOT belong to the group of
Halogens?
В. СІ
B. I
C. H
D. F
8. Metals vary in reactivity. The most reactive metals will react even with cold
water while the least will not react even with acid. The ease and speed with
which a metal reacts with another substance is called its reactivity. Which of
these elements can be more reactive than Aluminum elements?
A. Cu
B. Fe
D. K
C. Ag​