Metals, for example Cesium and Francium
Answer:
0.1066 hours
Explanation:
A common pesticide degrades in a first-order process with a rate constant (k) of 6.5 1/hours. We can calculate its half-life (t1/2), that is, the times that it takes for its concentration to be halved, using the following expression.
t1/2 = ln2/k
t1/2 = ln2/6.5 h⁻¹
t1/2 = 0.1066 h
The half-life of the pesticide is 0.1066 hours.
The filament holds up the anther so that pollination and fertilization can occur!
Answer:
D.) H-O
Explanation:
Polarity is determined based on the difference in electronegativity of the atoms. The greater the difference, the more polar the bond. The general trend is that the atoms in the top-right corner of the periodic table are the most electronegative.
A.) is incorrect because H-H has no electronegativity difference, making it nonpolar.
B.) and C.) are incorrect because their electronegativity differences are not the greatest.
D.) is correct because the electronegativity difference between the H and O is the greatest.
The atomic number of Be is 4, and so it has 2 shells. There are valence electrons in the second, which is the outermost, shell of Be. To get the element with one more shell, there would be 3 shells on the new element, and 1 less valence electron, so the new element should have 1 valence electron. Sodium is the element with 3 shells, and one valence electron which fits perfectly into the description.
