Answer:
Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.
Explanation:
True, if you would like an example look at Indian arrow heads or early architecture all use rocks.
Answer:
calcium chloride deihydrate
Explanation:
Quite a number of properties varies across a period. Some remains constant whereas others decreases.
As one moves from left to right;
- The energy level remains the same.
- The ionization energy increases progressively as a result of increasing nuclear charge.
- Electron affinity increases from left to right.
- Electronegativity increases.
- Electropositivity decreases.
learn more:
Periodic table brainly.com/question/2014634
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