5. Due to its strength and lightweight, magnesium is often used in the construction of racing cars and missiles. Magnesium consists of three
isotopes in the following percentages: 78.99 %magnesium-24, 10.00 %
magnesium-25, and 11.01 % magnesium-26*
24.51 amu
23.41 amu
24.32 amu
24.40 amu

hi,

the answer is d, it has indefinite shape but definite volume.

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c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

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