Eric Belll
New member
...thank you so much? 17. In organizing his periodic table, Mendeleev gave the name eka-aluminum to a
A. compound containing a unique form of aluminum
B. mixture of aluminum and an unknown element
C. unknown element he predicted would have properties similar to those of aluminum
D. rare isotope of aluminum that had unknown properties
18. When moving from left to right across a row of the periodic table, which of the following values increases by exactly one from element to element?
A. isotope number
B. atomic number
C. atomic mass unit
D. mass number
19. As you move from left to right across a period, the number of valence electrons
A. increases
B. stays the same
C. increases and then decreases
D. decreases
20. Compared with group 2A elements, group 6A elements have
A. more atoms in the ground state
B. more valence electrons
C. more isotopes
D. fewer valence electrons
A. compound containing a unique form of aluminum
B. mixture of aluminum and an unknown element
C. unknown element he predicted would have properties similar to those of aluminum
D. rare isotope of aluminum that had unknown properties
18. When moving from left to right across a row of the periodic table, which of the following values increases by exactly one from element to element?
A. isotope number
B. atomic number
C. atomic mass unit
D. mass number
19. As you move from left to right across a period, the number of valence electrons
A. increases
B. stays the same
C. increases and then decreases
D. decreases
20. Compared with group 2A elements, group 6A elements have
A. more atoms in the ground state
B. more valence electrons
C. more isotopes
D. fewer valence electrons