Which of the following statements is/are true for all the alkali metals ?
A. Their nitrates decompose on heating to give `NO_(2) and O_(2)`.
B. Their corbonates decompose on heatig to give `CO_(2)` and metal oxide.
C. They react with oxygen to give mainly the oxide `MO_(2)`
D. They react with halogens to give halides `M^(+)X^(-)`.
