A.Mg2+.
B.Ag+.
C.Fe2+.
D.Cr2+.

A.Ca.
B.Na.
C.Cu.
D.Al.

A.Cu.
B.Al.
C.Fe.
D.Mg.

A.Tính khử.
B.Tính oxi hóa.
C.Tính axit.
D.Tính bazơ.

A.Al, Fe.
B.Au, Pt.
C.Al, Au.
D.Fe, Pt.

A.SO2.
B.CO2.
C.CO.
D.NO2.

A.Zn.
B.Ag.
C.Cr.
D.Cu.

A.45,6 gam.
B.60,0 gam.
C.56,4 gam.
D.67,5 gam.

A.14,0 gam.
B.12,6 gam.
C.9,8 gam.
D.8,4 gam.

A.About 54% of the world's population will live in cities by 2050.
B.Risks cannot be addressed effectively no matter how well cities are governed.
C.Urbanization brings important benefits for development as well.
D.Rapidly increasing population density can help solve poverty.