Equation for Half life :
A = a(0.5)^(t/h)
A is current amount, "a" is initial amount, h is halflife, t is time
5 = 40(0.5)^(t/1.3x10^9)
5/40 = (0.5)^(t/1.3x10^9)
take the log of both sides , power rule
Log(5/40) = (t/1.3x10^9) * Log(0.5)
(1.3x10^9) * Log(5/40) / Log(0.5) = t
3.9x10^9 years = t
And if you think about what a half life is, the time it take for the amount to reduce to half.
40/2 = 20
20/2 = 10
10/2 = 5
It went through 3 half-lifes
3 * 1.3x10^9 = 3.9x10^9 years
Metals are located on the left of the periodic table, and nonmetals are located on the upper right.
Explanation: Metals: Lustrous (shiny)
Good conductors of heat and electricity.
High melting point.
High density (heavy for their size)
Malleable (can be hammered)
Ductile (can be drawn into wires)
Usually solid at room temperature (an exception is mercury)
Opaque as a thin sheet (can't see through metals)
Nonmetals: High ionization energies.
High electronegativities.
Poor thermal conductors.
Poor electrical conductors.
Brittle solids—not malleable or ductile.
Little or no metallic luster.
Gain electrons easily.
Dull, not metallic-shiny, although they may be colorful
Answer: (give brainliest)
proton- a stable particle with positive charge equal to the negative charge of an electron
electron cloud- the system of electrons surrounding the nucleus of an atom.
nucleus- A nucleolus is the largest structure within the nucleus of a eukaryotic cell.
electron- Electrons are the smallest of the particles that make up an atom, and they carry a negative charge.
neutron- a subatomic particle with 0 charge and mass about equal to a proton; enters into the structure of the atomic nucleus.
Explanation:
Answer:
Student 4, because a Brønsted-Lowry base always accepts a proton from an acid to form a conjugate acid.
Explanation:
That's the definition of a Brønsted-Lowry base.
Student 2 is wrong. All bases will neutralize acids. That doesn't tell you the type of base.
Student 3 is wrong. The pH of a solution doesn't tell you the type of base.
Student 1 is wrong. Both Arrhenius and Brønsted-Lowry bases react with acids to produce water and a salt.
